the Americans have never defeated their outward Imperialism. It has always been defeated by their victims themselves.

Yes, and I think this point is very important. This is true pretty much anywhere that imperialism has been defeated, even temporarily, and we shouldn’t expect it to happen the other way around. In fact, the US being a settler colony makes this already unrealistic scenario even more unrealistic. The people of Imperial core nations simply benefit too much. That’s where revolutionary defeatism comes in. In cases where an imperialist/colonialist nation was defeated militarily (e.g. in a world war), the colonies of those nations that won independence still had to fight for it. It wasn’t ever just given. And cases where it might seem like it was, are cases where imperialist ties still persisted and the formerly colonized nations were still exploited through imperialism.

I think the fact that some people don’t understand this and push basically a white savior narrative in which settlers in the US have a revolution or do something to free all the lands the US extracts wealth from is a symptom of the prevalent and baked in white supremacy of these settler states. There is a dialectical relationship between the colonized and the colonizer classes that also needs to be resolved in order to actually build towards communism and that resolution will not come from the class in power just stepping down. I’m not a settler myself so I guess it’s easier to see this more clearly from the outside, but our comrades that are settlers need to do this analysis and self-crit accordingly. No one is saying that white communists in the US can’t support these indigenous and black movements, in fact they have to support them against the mass of settlers but they cannot replace them.