Satan vs. God.

How come people who 'worship' Satan and/or use him as an idol (fictional or not to them) are deemed as dangerous, wicked, and evil in our society...but, people who 'worship' a God who has killed millions of people, will send you to hell for eternity, and is basically a psychotic deity, are usually deemed as good, pure, and more socially acceptable? (not by all, speaking for society as a whole).

I wonder if anyone who is religious have actually stopped to think about this concept? Or they're told to just not question it?

This is what made me confused as a child/early teen.