Every country being pressured under capitalist imperialism is fundamentally different from revolutionary internationalism. What we have happening on Earth is absolutely nothing like a hypothetical that uplifts people out of their material conditions; imperialist "development" is not internationalist, it's superexploitation. There is no interest to improve anything for anyone but the rich.

Furthermore, indigenous people weren't peacefully assimilated, they were killed and imprisoned and enslaved and raped and had their children kidnapped and their languages/cultures made illegal and all of this was done through the use of incredible violence. Manifest destiny was all just colonialist propaganda. The White Man's burden was a lie that whitey told himself to not feel bad about murdering and raping everyone. Never, at any point, did the empires actually try to make things better for other people around the world. It was always for themselves.