The Christian position is that you, arguing about Hitlers relative-to-you evil is the same as one grain of sand on a beach arguing that it is closer to the sun that the grain of sand next to it.
But even relative to the sun, that's true. They only become equidistant when the measuring error is larger than the differential distance.
The same with God. God may be so good that the difference between Hitler and you is not very large by comparison, but the difference is still there. The only way that you and Hitler are the same on the evil-ness scale is if God isn't capable of discerning minute differences in evil.
Judging from the Bible, and the fervor with which Christians rush to condemn certain acts, particularly sexual ones, under the ageis of God's law, we know that's not the case. And it certainly wouldn't be consistent with an all-powerful, all-percieving God. To suggest that God can't discern something that is obvious to us - that Hitler is a much more evil person than your average human being - diminishes God.
It really kind of proves to me that, to believers, concepts like "all-powerful" and "all-knowing" don't really have much meaning. They certainly don't spend a lot of time thinking about the ramifications for their beliefs if those things are true.