Why do atheists criticize Christians for their beliefs, but won't admit that their belief that God definitely does not exist is a guess?

Why? Because Christian beliefs misrepresent how reality actually works. Modern people with an adequate education know that physical matter is the basis of objective reality and that mental experiences are unreal abstractions, created within each person's living brain. Christianity has been attempting to undermine humanity's intellectual and social progress for 1630 years. It's also been 373 years since Rene Descartes first explained the distinction between reality and perception. These days, educated people are sick and tired of superstitious religion getting in the way of progress.

While Christians are entitled to their own beliefs, that does not give them license to browbeat and harass those who prefer factual knowledge to superstitious ignorance. I'm an atheist because I know that only physical matter and energy can actually "exist" within our universe. If God were to exist, He would have to be made of the same substance as everything else which actually exists. That being the case, there would then be electromagnetic evidence of God's existence and there simply is none.

The truth is, the first Roman Catholics embraced the philosophies of Aristotle and Plato, which they combined with early Christian folktales when they created the New Testament and Scholastic theology. The problem is, humanity has known physical matter, not subjective mental experience, is the basis of objective reality for almost four hundred years and Christianity has done nothing to reform its obsolete theology. It's gotten to the point that superstitious religion has become a persistent threat to human intellectual and social progress. To insure further human prosperity, it is necessary to have a clear understanding of how the physical reality we inhabit actually does work. Continuing to purport that subjective mental experiences (beliefs) are the basis of reality is sheer superstition and dangerously irresponsible. Humanity has far more potential than to continue forever propagating the superstitions of our ignorant ancestors.

I oppose Christianity because I want a much brighter future for my species than relentlessly pretending our thoughts are real.

The difference being that the belief that god doesn't exist is an educated guess, while the belief that god does exist is not.

Sure, it's entirely possible that there's a supreme being out there that made everything.

Is it probable? About as probable as there being a creature made out of peanut butter sitting on a distant moon someplace in the galaxy.

In short, our view is not based on "nothing but faith". Such an argument is typical of a theist to make, and not unlike simply saying, "Oh yeah!? Well YOU have to prove god doesn't exist, or else he does!" Except…it doesn't work that way. At all.

The only way primitive religion exists today is through the child abuse of forcing it into very, very young children but thanks to better education and growing intellects so many teens are able to discover the truth, throw off the indoctrination and step into the real world!

So atheism is not a conscious decision or a belief but a realisation!

The first person to produce a single tiny little piece of verifiable evidence for any god will become world famous and mega rich!

Academia states that in the absence of any sort of evidence of the existence of something it must be deemed not to exist until verifiable evidence is found - thus god is held not to exist pending some sort of verifiable evidence.

The bible is what is called "Faction” A fictional story set in a factual time and place. Thus the time, place and real historical characters are all correct but the fictional characters and stories are not!

Most atheists simply say that there is not enough evidence to convince them of a god, rather than saying that a god definitely does not exist.

I'm curious, though. Most believers insist that their version of god definitely does exist, even though they can't prove it with objective evidence. Why is it okay for them to make such statements?

Nice attempt at twisted logic. I can't prove something does not exist so therefore it must. I do not believe in pixies but I can't prove they don't as you can not prove a negative. Therefore even though there is no evidence by your thinking they must exists. Can you see the flaw in your argument? By the way, I don't condemn faith. I condemn that try to force that faith onto others.

Typical BS. Atheists believe that there is no god, but that is not based on faith. The belief is based on the available evidence. No available evidence supports the existence of a God; not the christian God, the Norse gods, or the Greek/Roman gods. There is also no evidence to support the existence of the boogeyman, leprechauns or winged horses. If there is no evidence that something exists you can still believe that it does based solely on faith (theists) or you can go with the evidence and not believe.

That is not faith that is logic. Unless you are willing to admit that leprechauns exist or that that the flying spaghetti monster exists because they are supported by the same evidence as your god than stop making the stupid claim that atheist's beliefs are based on faith.

You don't understand what an atheist is.

What you describe is not an atheist - an athiest is someone who does not accept the proposition that gods exist.

This is not the same as denying that gods exist, it is the same as saying I have not been adequately convinced that gods exist.

That is all, it is a perfectly reasonable position.

Under the "scientific method" no one can claim gods don't exist is a fact. However, where the chances of the existence of something is so infinitessimaly small it is unworthy of consideration we allow ourselves to claim they do not exist i.e. under the scientific method no one can categorically claim santa, pixies and fairies don't exist but we have no problem claiming they don't.

However, as santa, pixies and fairies haven't given us an eyewitness account of their creation of the universe and got the sequence wrong, we can safely say, they are more possible than your god.

I don't say "God definitely does not exist".

I say "God is imaginary".

And that's what he remains until provide some evidence other than what you believe.

BTW, what's your basis other than your personal imagination (your guess) for following God and ignoring all other imaginary authority figures?

I have not said god definitely doesn't exist, but if you fail to provide evidence that he does then nonexistence is the default position. Otherwise everything would exist.