It’s not about communism or capitalism, it’s about historical mass death events. It’s just a coincidence some of the largest mass deaths happened under communism. For example, I’m sure the lives of Ukrainians were greatly improved sometime after the mass starvations during the holodomor.
I don’t even disagree with what you’re saying about the US but using this to imply that communist regimes of China and Russia were good actually is insane to me. Not as bad as fallacy in full effect.