A Thought on Atheism

It seems to come up a lot whether atheism should be considered a religion or not. I keep getting the feeling that both theists and atheists get very bitchy and butthurt when people think it in fact is one.
Which is the point at which, to me, this very simple question pops up: ...Why?!
Admittedly, I have my opinions on this. But. Why is it such a touchy subject? Does it in any way degrade atheism to be defined as a religion? Does it in any way sully any other belief system to fall under the same term as believing there is nothing?

Actually, I spent a few seconds on thinking about how to phrase the last part of that sentence. Because "not believing anything" would've been wrong - you do believe to know that there is nothing to believe in. "Believe in nothing" would be the definition of nihilism. Terminology, once again, is everything

Anyway. Back to my actual point. The reason I decided to write this journal entry was the little discussion I accidentally started beneath a stamp. I felt like sharing the part of my last comment stating my view on this issue:

"(...) Reading your comment, you keep bringing up that you don't believe what other people do believe. That is exactly it. Belief. Sure atheists have "evidence" for thinking it's highly unlikely or even impossible that god exists, but theists have proof that he does - not necessarily proof that you or I would call bullet proof evidence, but the same goes the other way around. But there is no surefire way to call this or that the absolute truth. You can go ahead and do so, no matter which side you're on. But you actually have no grounds for it, theist or atheist.
Atheists therefore too choose to believe. Not in something, but they do believe that there is no divine existence. Now that may be the exact counterpart to classic religions which normally are built around some higher power, but it is, nevertheless, a belief system. Neither theists nor atheists know. Both camps think they do and they both call the other possibility ridiculous (at least the militant members), but the reason both sides still exist is because there is no definite proof. Both sides will try to tell you there is. But the mere fact that they both still have room to stand by their own belief proves them wrong in exactly that.

Nothing we think to know about the existence or non-existence of a god is more than theories. Everyone decides for themselves which one they deem to be the most plausible one or what they want to believe. But as long as atheism has no more hard proof on its hands than theism, it remains a belief system - and therefore a sort of religion."

Go here for the full discussion.