In my opinion Atheism is just as much a religion as Scientology or Christianity or any other faith.
The key difference is that atheists tend to think scientifically, and a good scientist builds their beliefs on scientifically determined facts.
A good atheist (and not all of them are) will change their views as the science changes. Religious believers, and other believers of an ideology, will hold on to their beliefs even when evidence strongly contradicts them.
Q: How can you belive in things for the sake of beliving in them when there is no proof, and how can you pick one belife system over another when they are all equally likely?
A: the answer is that the quetion applies to Atheism as well as religion.
It does not apply to scientifically minded atheists. Their belief system is based on what there is evidence for. Of course, some people who call themselves atheists might not really be scientifically minded. But, don't be fooled into thinking science is the same as religion.
Q: What about <Insert logical inconsistency in religion of your choice>?
A: Beats me, what happened five minutes before the big bang?
Nobody believes in the Big Bang all willy-nilly, just for the sake of it. Or, if anyone does, they are a fool.
The "Big Bang" provides a scientific model for the origins of our known universe, based on observations made in the cosmos, and in studies of physics. Like all models, it is provisional - it is subject to change, depending on the outcome of future evidence.
Many people are under the mistaken belief that there was "nothing" in the universe before the Big Bang. Technically, this might not be true. Scientists refer to the "time" before the Big Bang as the "Initial Condition" of the Universe.
What was the Initial Condition like? Well, unfortunately science can not determine that conclusively, yet. But, that does not mean the Big Bang model doesn't hold any value. It is meaningful to scientists because it provides a useful explanation for what goes on in their physics experiments.
So, "5 minutes before the Big Bang" is anyone's guess, right now. However, I would caution against asserting the supernatural, here, and calling such an appeal "science". Science doesn't work like that. Only your personal philosophy might.