There are many popular myths about atheism and atheists which claim that people are atheists on account of some sort of rebellion (against god, religion, church, families, fathers, etc.) or pride. These myths come primarily from Christians whose religious mythology gives an important place to rebellion against divine rules as the origin of evil in the world (Satan is depicted as having rebelled against God). At most, these myths might be true of some but not all or even most atheists; even if true, however, none of these myths would have any implications for the truth or reasonableness of atheism itself.
This misconception is similar to the claim that atheists don’t believe in God in order to be free to behave immorally. This is an attempt to attribute a person’s disbelief to a desire to evade what they don’t like about God. All that is happening here is that the theist is making a claim about why a person is an atheist and then attacking that motivation. This does not, however, say anything about atheism itself. No reasons are given for thinking that atheism is an unreasonable position and no reasons are given for believing in any gods.
It is true that there are people who have become atheists due to anger at their church and/or religious institutions generally. It is also true that some of these same atheists have not let go of their anger even today, allowing it to influence their critiques of religion and theism. It's wrong, however, to conclude that therefore atheism is necessarily or inherently an act of rebellion against church and religion. Many, if not most, atheists come to atheism via means other than rebellion. Even if atheists were rebelling, though, this would say nothing about the reasonableness of atheism itself.
Most people acquire their religion through the influence of their families — whatever religion one's parents and siblings belong to, that is the religion a person learns about from their earliest years and to which a person professes adherence through most, if not all of their life. Thus, it may seem reasonable to conclude that anyone who deliberately abandons the religion of their parents must be "acting out" and rebelling against their family. This may be true about some people, but certainly not about atheists generally and it's rarely something that persists or remains a basis for atheism.
It sounds bizarre to suggest that atheism has anything to do with one's relationship with their father, but this myth has become popular due to the efforts of Paul Vitz, a psychologist and former atheist who argues that the basis of atheism can be found in a person's defective relationship with their father. Thus the denial of God — the Heavenly Father — is a reflection of our inability to be close to an earthly father. There is no reliable, scientific evidence to support this, just cherry-picked data from a few biographical studies.
It isn’t uncommon for some theists to say that atheism requires such extensive knowledge that an atheist would have to actually be God in order to deny God. This argument makes the mistake of assuming that an atheist, to be an atheist, must have certain knowledge that no God or gods exist. It also makes the mistake of assuming that universal negatives cannot be proven. Neither is true. Atheism is just the absence of belief in gods, not an attitude of certainty that no gods exist. Even when an atheist denies the existence of any gods, it's not impossible to prove a negative.
This particular myth about atheists doesn't specifically address atheism itself — it doesn't come out and say that atheism is wrong nor does it argue that their theism is more reasonable. Instead, it is a personal attack on the character of the atheist being addressed. The reason why is not clear, but it appears to be an attempt to imply that atheism is wrong because atheists share some negative attribute. Even if this myth were true, however, it would not be a reason to reject atheism. Theism can't be rendered reasonable or rational simply if atheists have an annoying attitude.
Sometimes people who don’t believe in gods are accused of wanting to be God themselves. This may be because some religious theists place their god in charge of everything in their lives — all of their decisions and choices are made on the basis of what they assume their god wants. Atheists, however, make decisions on their own and thus might appear to be putting themselves in the place where others have their god. Thus, atheists may appear to be assuming the position of God. Even if this misconception is understandable, though, it doesn't justify the idea that atheists want to be God.
The myth that atheists are angry in general is itself already popular, but the myth that atheists are angry specifically at God for not having done what they want may be more popular. It combines the idea that atheists are angry, that they are prideful enough to think that they know better than God, and that they are rebelling against what God wants. Atheists are thus attacked from a variety of convenient directions, except for the fact that the claim is all wrong. If atheists were angry at God, then they would believe in the existence of God and so they would be angry theists, not atheists.
Some people are so sure of the existence of their god that they have trouble imagining that someone else could honestly not feel the same way. Because honest disagreement is not possible, the cause of disbelief must be denial. Such an attitude has a venerable pedigree, going right back to Paul, but it's not a fair, logical, or even very honest argument to make. Atheists are no more in denial than theists are - atheists simply disagree with theists, and for good reasons. If a person says that they don't believe in any gods, it's rude and arrogant to pretend that they aren't correct.
There are many popular myths about atheists which portray them as not really being serious about disbelieving, while other myths suggest atheists are in denial about what they really think. This myth combines both and presents them at the same time. First the atheist is only proclaiming atheism in order to be "contrary" with others while at the same time denying what they really believe - someday, they will admit the truth and will give up acting like they don't believe in God.
It's not uncommon for atheists to argue that religion and theism are a sort of crutch that makes it easier for people to deal with problems in life, so perhaps it's not a surprise that some might try to turn this around and argue that atheism is actually the crutch. How, though, can mere disbelief in gods act like a crutch in any manner - no matter how metaphorical? The problem lies in misrepresenting atheism as if it were a belief system. If that were true, it might theoretically be possible to think that atheism does the things described - but from a false premise, false conclusions quickly follow.
Atheists are frequently accused of being arrogant for thinking that they know too much. Sometimes they are accused of thinking they can know God doesn't exist (but it's OK for theists to say they know God does exist). Other times they are accused of presuming to know more than intelligent theists who believe in God (but it's OK for theists to presume to know more than intelligent atheists). Here, we have the accusation that atheists think nothing is beyond human knowledge.
