Why do people think atheists and agnostics are some sort of "club"?

Shh! If you tell everybody, I won't be able to collect membership fees anymore!

I think what you are really asking is;

"Why do people make wide generalizations and assumptions?"

I think the answer is that "people" are either too lazy or perhaps too self-interested to make an effort to consider others as individuals, each with their own minds and opinions and each worthy of respect and thoughtful consideration. I suspect that most of those who make generalizations like this one would rather just make a rule than take the time to think about each individual case.

People you disagree with are easier to accept if you pigeonhole them. Also if you project your own world view on them instead of taking the trouble to find out what they're really about.

What amuses me is the constant claims that anyone who doesn't believe in Christianity must be ignorant of it, when in fact most non-believers are people who were brought up as Christians and for one reason or another no longer have the faith.

I think it's because Christians tend to be so hostile to anybody not believing in their god that they have to form atheism/agnosticism into religions in their mind, so they know what they are opposing. They can't stand that somebody would not only operate with a total lack of religious faith, but DEFINE themselves as a group without any reference to religion whatsoever. So they have to try and redefine atheists as a creature they know how to combat (i.e., members of another, non-One-True faith). A worldview without any god is just beyond their comprehension.

can you cite anyone who does, or are you just typing for the sake of typing? i've never encountered anyone who thinks that atheists and agnostics are the same thing...i will agree that there can be friction when someone touts their idea as better; i get slammed on a daily basis by atheists on this site-i suppose it makes them feel better about themselves, and it often amuses me...

They try to pigeon hole people into categories in order to make hasty generalizations. It is human nature and it's used for cognitive economy. But don't worry too much about it. Don't take it personally and move on, it's only an online forum.

Because a real atheist will not take any interest in religion and

will never start a campaign to publicize his beliefs because he expects no reward from God. But there is a campaign under way from an invisible organization to popularize atheism, lending credence to its secret aims.

Javed Iqbal

Because we are so wicked cool, people figure we must have formed an elite club to concentrate the coolness

Atheist mafia? There ain't no such thing. That's slander.

The "AM" after my screen name?

Uhhhhh.... it's because I really like morningtime.

Yeah, ummm....that's right. It's because I love the morning.

We should have a club though... not like a church but... it would be nice to have a place to hang out with folks somewhat like minded...