Do you feel most of Christendom has put aside the teachings of the Apostle Paul and if so, Why?

No, not most, but certainly SOME. Some liberal New Testament scholars from secular universities appear to be promoting a “New Perspective on Paul”. One such proponent is N.T. Wright, a noted Bible scholar and Bishop in the Anglican Church, whose books seem to be influencing the spread of this troublesome teaching in evangelical churches. Here is a short extract from an article about it:

"There are four basic tenets of “New Perspective on Paul.” First is the belief that Christians misunderstand Judaism of the first century. They say that Paul was not battling against Jews who were promoting a religion of self-righteousness and works-based salvation and that the Pharisees were not legalists.

The second tenet is that Paul really did not have a problem with the doctrine of salvation taught by the Jewish leaders of his day. His disagreement with them was simply over how they treated the Gentiles and not a fundamental difference over how one is saved or justified before a holy God.

The third tenet of the “New Perspective on Paul” teaching is that the gospel is about the Lordship of Christ and not a message of personal salvation and individual redemption from the condemnation of sin. No one can make Christ Lord of his life without first being cleansed of sin and indwelt by the Holy Spirit. Only the Spirit of God can empower us to yield to the lordship of Christ.

The fourth and the most serious unbiblical tenet of the “New Perspective on Paul” teaching is the denial of the doctrine of justification by faith, a central and non-negotiable Christian doctrine. According to proponents of this unbiblical teaching they claim, when Paul wrote about justification, he was speaking of how one could tell if a person was “a member of the covenant family.”

The problem with this tenet of the “New Perspective on Paul” is that it distorts the biblical teaching on justification by faith and instead teaches that Paul’s doctrine of justification was only concerned with the Gentiles’ standing in the covenant community and not at all about a guilty sinner being declared just before a holy and righteous God. Simply put, we cannot disregard or redefine justification and still be considered Christian or biblical. In his writings, N.T. Wright often argues against the imputed righteousness of Christ, which is the heart and soul of the true gospel (2 Corinthians 5:21)."

There are denominations who are legalistic and who promote a “justification by works” theology. The Bible says the gospel “is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek” (Romans 1:16). Yet some denominations say that believing is not sufficient, that you have to somehow “earn the right to be declared righteous” by virtue of your unswerving loyalty and obedience to the denomination you belong to and by doing good works. Some denominations claim that when Paul wrote about justification, he was not speaking of personal and individual justification whereby a guilty sinner is declared righteous on the basis of his faith in Christ and Christ’s righteousness being imputed to the sinner, but that only a limited number can enter into the new covenant and only they can have Christ Jesus as their Mediator.

Hmmm, sounds a lot like Jehovah’s Witnesses to me, especially with regard to their belief that God has finished with the Jewish nation and that their "anointed remnant" are now "spiritual Israel" - Jehovah's chosen people.

Which specific teachings of Paul are you referencing?

Yes, probably because Paul’s theology matches that of Jesus, and people find it hard to do what Jesus says to do.

Because they do not believe Galatians 1:11-12 and 2 Peter 3:15-16. Therefore anyone with that mind-set does not love the truth, 2 Thessalonians 2:9-12

No not at all

I think some people who try to get the bible to fit their favorite sins (Aka sexual perversions) try and minimize Paul

but they are not Christian anyway, if they are seeking their sin above God

I think that most of Christendom has put aside SOME of the teachings of Paul, because they recognise how silly they are. There are plenty of Christian men who wear long hair, for example, despite Paul's daft proclamation on the subject.

Most Christians have no idea what you are talking about...

Who was the Apostle Paul? And when did he live?

And what did he teach?

MOST of Christendom has, yes, because it requires so much work. I don't know ANY Christian who helps widows and orphans as much as I do as an atheist because they prefer to be lazy and defiant.

Belief only is easy and requires no effort.

No.

No. Some are just reinterpreting it.