They don't have to sign up.
They are not signing up.
You didn't sign up for the terrorist club did you?
Are you purposefully being antagonistic and thick, or do you really not understand???
People accuse Muslims of being terrorists and that bothers you because you are a Muslim and are NOT a terrorist.
Then you turn around and accuse atheists of many different things which many of them are not, but then say it shouldn't bother them if it does not apply to them?
Do you honestly not see the bald-faced hypocricy in that?