Please let me know if this community is not the best place for this post.

When I was a teenager, and even in my twenties, I used to be quite idealistic, naive, and somewhat radical, believing that all humans have the capacity to be good, and that the only thing preventing utopia where all live in abundance were the historical shackles of national/cultural/religious identities. As in, humans would for sure all get along, if only there were no major reasons for any "us vs them" type thinking.

But the older I get, the more my thoughts on the topic have shifted. My idealism has constantly been worn down by finding out about more and more people who would be happy to fuck over every single other person on this planet if it meant they could get a bit further "ahead" than everybody else. But even on a much smaller scale, after establishing my own family and building my home, at some point I realised that I would personally also be willing to go to extreme lengths if necessary to protect the way of life of my loved ones, including picking up a gun if our neighbouring country decides we should no longer have our freedom - this is something I would have considered "idiotic patriotism" when I was younger. Basically, this means I would also be willing to fuck up the lives of others in order to improve the lives of my family, and I think the same is true for most people.

What I'm getting at is that I think there are lots of reasons that people can have to hurt other humans, ranging from psychotic greed to a strong commitment to close ones. I think this is just human nature. I'm using the word "hurt" here in a very broad sense, including taking advantage of somebody, etc.

If indeed this is human nature, and humans are willing to exploit others to try and improve the situation for themselves and their loved ones, how can communism work? Would we not need to "evolve" to a new stage of humanity first, where people are capable of putting the needs of society above their own desires?

I apologise if this is a dumb question with some obvious answer, I admit I have not read any books on communism and am probably missing some key points.