Woodrow Wilson.
More Teddy Roosevelt, Yurope doesnt have a legitimate reason to despise muricans, Jim Crow laws don't happen and world politics would be less polarized.
Muhammad ibn Saud.
Founder of the ruling dynasty in Saudi Arabia, which helped salafis rise. Granted them rising is more due to the Sykes-Picot agreements, but they existing was always a treath.
Joseph Mengele
I know is too easy but OP just said not Hitler or Stalin.
Hosni Mubarak
This pigdog just makes me sick. Corrupt deviant and disgusting.