You're making this way too complicated. It's really very simple:
I can't choose to become invisible. Does that mean I don't have free will? Surely God could have created a world in which I could choose to become invisible.
If the God you believe in exists, he chose exactly what I, and everyone else, can and cannot do. Hitler could kill millions of people because God chose to put that within the scope of his decision-making. I cannot choose to become invisible because God chose to put that outside the scope of my decision-making.
How can you judge the God you believe in as worthy of worship when he chose to make it possible for Hitler to decide to kill millions of people? What argument can you possibly use that he had to give Hitler that choice that doesn't also show that he has to give me the choice to become invisible -- which he did not do?
(And, of course, you are right. I don't believe that the God you believe in exists, or even could exist. One of the reasons is all the obvious contradictions, such as this very one.)