Oh wow you just reminded me I forgot to include the nonsensical human nature argument. Yes I'm sure a system that rewards the worst qualities in human beings is the right one (capitalism).

Human nature had changed overtime based on the social relations embedded in modes of production. It underwent massive changes from feudalism to today's capitalism and will do the same at the next period.

To your last point, if you understand dialectical materialism, hegemony and imperialism in their role of stifling alternative systems, this sort of statement would not need to be made. It also ignores the great examples and prototypes we have/have had. USSR being the first, before it fell to counter revolution. China being the continuance and correction of those errors, displaying the true essence of Marxism; adaptability, criticism and self criticism in the pursuit of a better world.