This is the problem with unbelievers - they'll attack the hell out of you for supporting the bible, and say God is evil, yet they'll then say that evil doesn't exist - and a child murderer is not evil.
Are you familiar with how argumentation works? It's common for opponents of a position to,
for the purpose of argument, adopt that position and then explore the logical contradictions that stem from it.
Maybe it wasn't made clear to you, but that's what's going on. I mean, didn't it seem somewhat weird for someone to say that there's no god, but then talk about the qualities god has?
I realize that it seems like "mental gymnastics" to you; really, it's just a form of argumentation. We don't really believe your god is evil, because we don't believe your god exists at all. What we're doing is showing you the inconsistency of your own beliefs. I'm sorry that such an advanced technique confuses you, but maybe that's just because atheists tend to be better at reasoning things out than believers, by virtue of so much practice at it.