Yeah of course, this meme is meant to be making fun of the idea that "human nature" (whatever that may be lol) in any way disproves communist or anticapitalist theory

But have humans have never had a non-hierarchical large scaled society?

Humans were constrained by their material conditions. Now that those material conditions have changed, their behaviors have changed to match. This is not a fixed state of affairs. Humans continue to transition between stages just like every other living being.

Greed is as much a part of modern human nature as fear and love. And it is the product of a social condition that rewards growth, punishes disobedience, and requires a larger community to reproduce itself. It is a consequence of social conditioning executed iteratively from parent to child. And a consequence of statistical survival and prosperity played out over populations.

What defines human action is not the basic libidinal impulse, but the interplay between people and their environments over lifetimes and generations. That's not socialism or capitalism at its root. Socialism and capitalism are simply fruits grown from the post-industrial branches of the tree of human history.

Greed isn't inescapably "human nature", but results from it under some basic conditions. The nature of enjoyment and suffering means the pursuit of enjoyment and avoidance of suffering as a biological imperative. Desperation, lack of cultural/learned empathy, cultural normalization of disparity, etc., can quickly allow unchecked greed. The same thing, with different conditions, can be said for... not sure there's a single word for it, but behavior motivated by empathy promoting equality and sharing and so on. The conditions actually kind of close to being the inverse of those for greed - some combination of not having desperation, having cultural/learned empathy, cultural normalization of economic equality, etc. Both types of thinking are just basically pro-social or anti-social thought with regard to material/economic gain, depending on what influences individual thinking.

And slavery isn't capitalism? Or is that cooperative because the slaveholder says "I have a knife and will kill you" and the slave says "I don't want to die" so it's mutual collaboration where the slave doesn't die but also is a slave?

Mesopotamians tracked agricultural debt on clay tablets in 3000 BC