Sure humans are cooperative, but but it's not an either/or scenario. Humans are often incredibly selfish at times, and even if not selfish are often focused on benefit for themselves.
And my point is that it's not unique to capitalism. Even prior to capitalism and under communism, humans are highly focused on benefit for themselves, even at the expense of others.
You are cherry-picking to come to that conclusion. Humans are constantly navigating the pull in either direction. On the one hand, they are pulled toward what benefits them, and on the other, to what benefits their group and to what gains them acceptance from said group. Often this means putting the group's needs on equal footing to the individuals.
You are correct that the pull towards the individuals' needs is not unique to capitalism. You are not correct that humans are "highly focused" on benefit for themselves at the expense of others.
I would say that some humans act as you say; but in the court of a king, your "group" reinforces behavior that is selfish on a societal level, so long as tribute is paid to the king.
Most people do not live in the court of a king. I live with a family. I put the needs of my family on equal footing with my own. I maintain that this arrangement is more common than not. For every ambitious individual there are countless thousands who want only to love and be loved.
You put your family’s needs on the same footing as your own. And you put those two needs far above people outside your family.
That’s exactly my point.
People sometimes act in the good of everyone, usually when the cost isn’t high. But otherwise they act in benefit of themselves or their group, often at the expense of the out group.
You don’t need capitalism for that to happen.
Agreed. I understand what you are saying. You don't need capitalism for absurdly selfish behavior. However, I don't know that a capitalist system, in its current, relatively unregulated form, is making humans less selfish.
The form of capitalism now gnawing away at US society is essentially shouting "the virtue of selfishness" from the rooftops. People respond to leadership, including moral leadership. There are better forms of capitalism that involve regulation and fairer taxation, such as we have had in the past, but no longer have now.
For a lot of people criticizing capitalism, the goal is not socialism but rather better capitalism.