It is not as if someone who is atheist is going to steal your first born child.
It is not as if someone of the faith is going to tie you down and convert you.
Granted, not all people care that much about what the person believes, but more of what they say.
It seems that a lot of people of the faith take it personally when an atheist says something against the religion, pointing out flaws in the logic.
And athiests seems to get all up in arms when a person of faith posts a cliche, factless religious 'oint.' I admit I am guilty of this every now and then.