Now I have to apologize for playing both sides of this conversation, but we've been working on this tribalism for a few hundred years, maybe if you were a better student of human history than I am you could make a case for a few thousand.
We have a way to go, but we have made at least some progress. Maybe in another few hundred years humans won't be so 'Us and Them'. Maybe materialism will be the next thing we work on. Who knows, maybe by the time we reach the next galaxy we'll have it sorted out.
It's human nature to crave sex, maybe not with every single person you meet, but certainly with more than a single partner in your entire life, right? For thousands of years, Christianity attempted to "work on this" aspect of human nature and make non-monogamous sexuality taboo. It was fairly successful at it. Yet (depending on your perspective) it only took somewhere between a few years and a few decades post-sexual revolution for it all to come crashing down spectacularly.
If the most powerful institution in the western world couldn't "fix" this aspect of human nature over millennia, it is sheer arrogance to think we can do better today.
Feminists have selected against male aggressive behavior in our education systems for decades. They have "successfully" ruined the lives of countless western boys and laid the foundation for immigrants from non-castrated cultures to take their stead with redoubled aggression. Turns out that it's much easier to beat boys into submission than it is to subvert female attraction to dominance.
We have a way to go, but we have made at least some progress. Maybe in another few hundred years humans won't be so 'Us and Them'. Maybe materialism will be the next thing we work on. Who knows, maybe by the time we reach the next galaxy we'll have it sorted out.