Why do some Christians cherrypick what they believe in the Bible?

Often because of false teachings about tithing.

First of all, note that tithing (giving ten percent) was only commanded under the old covenant.

The old covenant was made only with the ancient Israelites (Ex 19:5-8; 34:27). It was never made with the Egyptians, Assyrians, Phoenicians or any other Gentiles. And then the Israelites broke that covenant anyway (Jer 31:31). Eventually it was superseded for all (Jew and Gentile alike) with the new covenant (Heb 7:22; 8:7,13) that was enacted after Jesus’ sacrifice on the cross (Mt 26:28). As a source for commandments, the old covenant is of no use unless those commandments are repeated in the new covenant. In fact, for one to use it to be righteous (i.e. to be justified) in God’s eyes is to fall from grace (Gal 5:4).

In contrast to tithing, there is a type of giving under the old covenant that parallels with that described in the new covenant: the freewill offering (Ex 35:29).

It is:

From the heart rather than a specific percentage (Ex 25:2; 2Cor 9:7),

In proportion to one’s blessings from God (Dt 16:10; 1Cor 16:2),

Given according to one’s ability (Ezra 2:68-69; 2Cor 8:12), and

Done in secret without boasting (Am 4:5; Lk 18:12; Mt 6:1-4).

The tithe was like a tax to pay for the services of the Levites and priests (Num 18:21,26-28). Since the Levites made up approximately ten percent of the nation of Israel, such a number was fair and made economic sense.

So you may ask yourself why some preachers still preach tithing from the Old Testament (but ignore other passages like those that command to kill those who break the Sabbath; Ex 35:2). It doesn’t make sense, does it (as well as confuses listeners about what parts of the old covenant they should obey)? Well, when things don’t make sense, nine times out of ten it’s about money, and such is the case here. Today, when preachers demand a tithe from members, if the church has more than say about 15 families in it per pastor, they are looking at a windfall. How do you think those preachers from those mega churches live such lives of luxury? If they taught giving as described in the new covenant, they fear having to buy a Kia rather than a Cadillac. (Therefore a church’s teaching on tithing can be used to quickly determine if the church is a true church of the Lord.) However, as mentioned earlier, per Gal 5:4, they preach like that at their peril.

Because of the error taught about tithing, many believers mistakenly conclude that it is also okay for them to pick and choose which parts of the Bible to abide by or ignore, just like their pastors do. Therefore for example, some choose to ignore what the Bible clearly says about the sinfulness of homosexuality, and think that no different than ignoring the command to kill Sabbath breakers. If the truth were taught that all old covenant commands (including tithing) have been superseded by the new covenant, there would be no confusion as to whether homosexuality is a sin since the prohibition against it is repeatedly repeated in the new covenant (Rom 1:26-27; 1Cor 6:9-10; 7:2; 1Tim 1:9-10; Jude 1:7).

It's absolutely necessary, though many deny doing it, as you see here. It's necessary because the Bible has many internally self-contradictory teachings and quotes, meaning that what is found in one part of the Bible is directly contradicted by another part, or is materially incompatible with another part.

An example of the first type would be when it says in Exodus that the God of Israel appeared, standing on a sapphire colored pavement, yet in John it says, "no one has seen God at any time."

An example of the second type would be how according to the Gospels (especially Mark, the one that was written first), Jesus taught repentance (which means to change one's mind or turn in a different direction), as well as saying that the kingdom of God is here and now, on Earth, within us and surrounding us, and also suddenly after his resurrection, appeared in a locked room to his followers, having them give him fish to eat and feel his wounds, while Paul, on the other hand, instead, taught that salvation comes through believing that Jesus is the son of God, raised from the dead, and whose death was an atoning substitutionary sacrifice for the sins of mankind, and that "flesh and blood cannot inherit the kingdom of God."

And btw, I was a believer for decades, and studied the Bible in depth for a period of several years, after a much longer, less formal familiarity with it growing up and in young adulthood.

We don't. We know what's in the Bible. You apparently don't. But I am interested in where you are getting the hair thing.

1Cor 11:13-14 Judge for yourselves: is it proper for a wife to pray to God with her head uncovered? Does not nature itself teach you that if a man wears long hair it is a disgrace for him,

Ezekiel 44:20 They shall not shave their heads or let their locks grow long; they shall surely trim the hair of their heads.

I think what you might be thinking of is specifically the Nazarite vow of seperation in Numbers 6.

"They shall not shave their heads or let their locks grow long; they shall surely trim the hair of their heads." But this is not a vow to never shave your head. It's a vow for Israelites not to shave their head during their time of separation. This is when a priest is called by the Lord, he makes a vow to take off on his own and meditate, pray and fast.

It is certainly not a command toward Christians to never cut their hair.

Harassing the people who this section is intended for is against community guidelines.

But I guess you "cherrypick" which community guidelines you choose to follow.

The accusation of cherry picking usually comes from someone who doesn't understand the Bible.

we do not cherry pick.

the bible talks about indentured servitude not enforced slavery

the bible does not tell every one you should never cut your hair

we don't cherry pick you don't know what your talking about

1 Corinthians 11:14Common English Bible (CEB)

14 Doesn’t nature itself teach you that if a man has long hair, it is a disgrace to him;

Sometimes people don't understand the context for certain passages found in scriptures.

"the Bible also promotes slavery and says you shouldn't cut your hair."

Sounds like you are the pot calling the kettle black.

"the Bible...promotes slavery."

Where does it "promote" slavery as you obviously perceive it?

Consider the following scriptures about slavery:

Matthew 24:45-47 "Who really is the faithful and discreet slave whom his master appointed over his domestics, to give them their food at the proper time? 46 Happy is that slave if his master on coming finds him doing so! 47 Truly I say to you, he will appoint him over all his belongings."

The conclusion there doesn't sound in any way like what a slave should expect, i.e. "he will appoint him over all his belongings," does it?

Galatians 5:13 "You were called to freedom, brothers; only do not use this freedom as an opportunity to pursue fleshly desires, but through love slave for one another."

According to the tenor of your question here, either you are mistaken about the word "slave" in the Bible, or the Bible is mistaken. Why? Because Christians have been "called to freedom," and yet should "through love slave for one another."

Your problem is that you haven't properly tried to understand what "slavery" is in the Bible.

Slaves were more like employees who had to be properly treated by their owners or masters, and under the Mosaic law a Hebrew slave or servant had to be released in the seventh year of his servitude or in the Jubilee year, depending upon which came first. [Exodus 21:2]

The Law protected slaves from brutalities. A slave was to be set at liberty if mistreatment by the master resulted in the loss of a tooth or an eye. As the usual value for a slave was 30 shekels (compare Ex 21:32), his liberation would have meant considerable loss to the master and, therefore, would have served as a strong deterrent against abuse.

Where somebody found themselves in dire financial straits [due to illness, injury, or whatever], selling themselves to someone else by becoming their slave or servant was a means to ensure that they could continue to be fed and clothed.

Joseph was sold into slavery and subsequently came to be in charge of everything belonging to Potiphar, a court official of Pharaoh. (Ge 39:1, 5, 6)

The Bible "says you shouldn't cut you hair." Another "cherry pick." Why?

It doesn't say YOU shouldn't cut your hair at all. What does the Bible ACTUALLY say about those to whom the most specific words of the Mosaic law were directed concerning their hair?

Ezekiel 44:15,20: "‘As for the Levitical priests...20 They should not shave their head or let the hair of their head grow long. They should trim the hair of their heads."

Disagrees completely with what you assert, doesn't it? While they were not to "shave their head," they nonetheless were to keep it "trimmed."

What about later, in Christian times?

1 Corinthians 11:14: "Does not nature itself teach you that long hair is a dishonor to a man, 15 but if a woman has long hair, it is a glory to her?"

Again, the only way that a man could not have long hair [except for something causing baldness] is if it has been cut, don't you agree?

So, what can we conclude?

You are misinformed about the meaning of slavery and cutting of hair in the Bible, but will you acknowledge it?

Confirmation bias.

They have this preformed idea of what should be in the bible, and so they adhere to those parts and forget/ignore the rest.

it's a big book, it's not possible to follow it all