I agree with both of y'all: Humans are inherently tribal, greedy, and selfish, and seek to better themselves and their kin at the expense of others.

Communism seeks to mitigate or avoid this human instinct, often failing.

Capitalism throws its hands in the air and says "ok, be greedy and selfish, ignore others and society, and if we're lucky, and it sometimes provides any societal benefit, that's purely incidental and secondary to you making money".