In an otherwise excellent article, this stands out as a shockingly nature-ignoring statement.

Genes matter.

For instance, mutations in neuroligin-3 cause high levels of aggressiveness in mice. Humans with variants of MAOA have dramatically increased propensity for psychopathy.

While there is still some sensitivity to environment remaining, your attempt to solve the "altruistic vs selfish" debate on human nature is stating, in effect, "No! There is no real human nature at all! Get the right environment and it's infinitely pliable!"

Except it's not true. There's a good deal of plasticity to respond to environment, but it's not unlimited. There is a great deal of evidence on this.

So, alas, there are "bad humans" (i.e. those who will repeatedly engage in highly antisocial behavior), and no prospects for ever completely avoiding this. Our job is to reduce how many end up that way, but also to make sure the ones who do don't cause too much suffering (hopefully while retaining as much quality of life and as worthwhile of a life as possible).