Yes. But obviously different people will try to read into this title in different ways, so here’s the way in which the answer to this question is yes.
If religion didn’t exist, atheism wouldn’t exist either, or rather, nobody would know that it existed. If religion didn’t exist, everyone would by default be atheist. Atheism could be defined as the absence of theistic beliefs. There are an infinite number of things that any one person does not believe in, and we don’t have words for all of them. The only reason atheism has been given a name and identified, is because it is distinct from religion.
How does this relate to the question though?
The reason many people consider themselves atheist, and acknowledge the concept, is because they see religion and think “No, I don’t like that.”. If religion didn’t exist, then people would have nothing to respond to. It just so happens that the majority of atheists live in the developed world. As the majority of the developed world has Christianity throughout its history, atheists are often responding to their opinion of Christianity.
However one shouldn’t see this as an angry response to Christianity and no other religions. The logic that propels a person towards atheism in the first place, is the same logic that makes them consider the same view towards all religions. As such, atheism is extended so that it is not just a non-Christian stance, but a non-religion one.
There are also various language barriers that influence the answer to our question. The dominant religion in the English-speaking world is Christianity, therefore the exposure you get as an English-speaker is mostly going to be on the subject of Christianity and Atheism.
The final factor that comes into play is one that reverses the question. Atheists commonly have an interest in challenging irrational statements. However very few of them are motivated to try to convert religious people. Religion on the other hand spews out an enormous quantity of converters and preachers. Many atheists might be happy to leave the religious alone, but should they come knocking at the door, they will challenge the irrational statements that are made.
This is the same in televised debates. The theists attack the atheists, and the atheists just defend themselves.
Of course one can think of numerous examples of when this is not the case. New Atheism asserts that religion should always be challenged. But the notion that Christianity in particular is under attack is due to geographical and linguistic factors, not because Atheists have a special hatred of Christianity.
I agree but this is not always the case… another thing: what would everyone do if you had 1 million dollar?