I would say that religionists think that atheists/agnostics are "attacking" their gods.
All we are asking for is some proof of a god or gods. We have studied the "holy books", we have gone to churches, mosques, temples and other "places of worship". We have tried to find this god, but so for have not found any proof that a creator god exists.
All the religionists need to do is present some logical proof of a god, have it verified by some sort of irrefutable test and we will become "believers".
Other than that, the biggest misconceptions are that since atheists/agnostics don't worship a god or gods, that they will go to hell, they worship Satan or the devil, they are trying to convert people to atheism, and they are blaspheming (attacking) their gods.
Apparently, logic, science, facts, and truth eludes them.