The indigenous peoples in the America's and Australia were almost wiped entirely out through disease, genocide and subjugation. In Africa and Asia the natives where not annihilated but where still victim to various brutal genocides, the Rubber Terror likely being the worst.
Right. Americans, Aboriginals and Maoris were decimated. So in their case, it would be hard to argue it turned out great.
Most borders in Africa and the Middle East were established by colonizers through war and genocide, leaving behind segregated communities and civil war.
Yes, they were. Entire civilizations and their people were wiped out. White and latinos didn't exist in the Americas before colonialism, and now they dominate. The African demography that exist today are a small fraction if the diversity that exists pre-colonization. ditto india
Disease mostly annihilated the natives anywhere outside of the Eurasia-Africa quarancule, hence Australia and the Americas mostly being populated by European-descended people now, rather than natives. Asia and Africa did better in that respect.