The allied forces have long exterminated an entire continent, namely Africa. Entire tribes have been wiped from the face of this earth, tribes that lasted for over 40.000 years.
Same cleansing still continues today with the Aboriginal Australians. Same thing happened with colonial England in Southeast Asia where tribes where also obliterated as "Savages".
The world would not be so different. Things change btu do so marginaly based on current politics determined by specific enviromental factors. For example you could have said that given the view of the States in the early 1900's women would never have had rights and blacks would remain slaves. Hitler would be dead much like Nixon and Roosvelt and things would take a new course. Gays would still exist so it would be impossible to eradicate them completely. Same thing applies to Jews.
Hitler may remind you had women equal to men before even US even thought about giving them rights. Similar respect was hold towards animals.
So as you can see your argument cannot hold. It is a post-hoc argument that can only be made after a situation was formed over the course of a century.
I can't emphasize enough how little our "victorious" books allow us to know.
RE: If Hitler Had Won