If you want the gist of this post, read "A VOTE OF NO CONFIDENCE: INTRODUCTION" before continuing.
Well then, here we go.
The Christian god (and most probably all the others too) is a good god. And an omnipotent god.
Now, we all know a certain someone called Adolf Hitler. You probably see where I'm going here... why didn't this good and all-powerful god save all those poor Jews and others during WW2?
The Christian community has a nice little, convenient, reason (loophole): freewill. The reason God isn't responsible for Hitler's misdeeds is because Hitler CHOSE to do those things. And (the ALL-POWERFUL) God couldn't do shit about that.
1. Good. The Christians have just proved that God is not, in fact, omnipotent.
To be continued...