I have been known to say : - I certainly do believe in something, I BELIEVE THAT YOU ARE ENTIRELY WRONG IN YOUR BELIEF IN GOD!

A preacher with all his tricks...

But logically believing in nothing is believing something but you al no is jack diddly do dah. Isn’t it great being is to varying degrees that we s free to ponder (fill in the blanks)

What it is is, Atheists subordinate themselves to no one.

I usually respond,

No. I actually believe in things that are real. You know things that can be demonstrated. Things that are based on facts. I'll grant you I don't believe in things that can not be demonstrated, you know, the imaginary asserted as facts because, unlike the theist, I recognize facts must be demonstrated. To assert Faith (belief without evidence) claims are a method to discover "Truth" (supported by facts that can be demonstrated) is dishonest. So because I value truth and honesty, I do not assert as truth things that can not be demonstrated to be true.

This usually gets them really annoyed and we wind up going back and forth a few times. They almost always see the light and leave with much less arrogance.

To answer your question: think they are taught this to support the necessary out-group homogeneity fallacy so they can maintain their superior self perception as the wise diverse group and if you are not like me, you are not as good etc.

We believe in many of the things they do with exception of the existence of a god/gods

Does it really matter what they say? Their lack of knowledge about Atheism is so deep that whatever they opine is meaningless.

useful and true

and i don't believe in god but i believe in carma and the universe and things i see not some imaginary being