The human condition is dictated by the hegemonic system that is governing.

Monopoly™ the game is structually engineered so that players kill the competition and secure the entire board. Would playing by the game's rules make me inherently a capitalist jerk? No, because they dictate my behaviour and not following them would put me outside the realm of the game (i.e. the system) resulting in my loss (decay).

If the capitalist system incentivizes me to outcompete others and hoard my wealth and, conversely, punishes me for my altruism; then, I am forced to play by the rules of such a system.

"Human nature" is much more complex to be reduced to just greed. This is what's so cool about being humans, we are so malleable and can be many many things either at once or separately.

Edit: I want to give some concrete examples to what I'm saying. Initially, the Google leadership was skeptical about AI funding, because of privacy and environmental concerns. Yet, as rival competition grew they backpedaled because this would mean their spot as the strongest teck company would be usurped. The late hop into AI funding and development heavily impacted their prospects and they remain falling behind in this respect (source). Here, we have an exemplary case of how the system automatically punishes hood deeds and reinforces predatory and greedy acts.