atheist do no more about religion that the believers.

Comment 5 by Arthur Eld

Can it be that theists that actually secretly feel doubts somehow find it more valid to reject atheism when they can call it an ideology? And if so: Why's that? Any answers or theories on this one?

Well that's easy enough. They're accusing you of being (or trying to make the audience consider the possiblity of you being) secretly under the sway of Satan, i.e. a Communist/Demoncrat/Totalitarian/Nazi.

More seriously, if it's just a single belief, not a total way of being, a tribal identity, it's difficult for them to comprehend. Indeed, one does require those things, they just don't get (or choose not to get) that within atheism those people choose or are born into are very disparate, or that they can come from things other than their particular religion and not necessarily be evil, or even very good.