It seems that most of the time, my discussions with people about socialism and communism end up on the topic of "but people are inherently bad, or at least a few people are, and will always take advatange of others. Even during natural disorders, some go steal everything in the stores while other help strangers"

I always have a hard time arguing that human nature depend on the environment, that it takes a few generations, and that there is probably always going to be violence but it's marginal and can be taken care of.

What main ideas am I missing? And how to argue about this and respond to this central idea that refrain a lot of liberals?

Thank you!

If you have any theory that you want to point at, that would also be great