tribalism got more people killed than any other thing in human history. People falsely believe that they will get hit in a battle due to the psychology of the crowd. Same applies for demonstrations in the streets, politics, football matches anything really. More people get in trouble because the mind stops being of an individual. it is rendered too basic towards a very basic goal. This is why groups are also so brutal.

An individual would be more in danger from other groups, sure. But a group cannot offer more safety.

Also, being in a group is also a selfish act towards self-preservation. You just admit you have to do some shit in order to belong. business as usual.

I don't think we understand the degree to which the apparent characteristics of human nature are actively modulated by environment.

we have a fairly good idea. Humans are not that complicated. they are much like any other animal. We just like to give too much credit to ourselves.