Why Don’t the Aliens

The Fermi Paradox, I think it is, that wonders why, if there is intelligent, extraterrestrial, space faring life in the universe, nobody’s ever visited.  At least, nobody’s ever landed in a highly visible milieu, emerged from their ship, and asked to be taken  to our  leader, or something like that.
Who would that leader be today?  Maybe  that’s part of the problem. They scout out our planet, they realize that we’re divided into  hundreds of nations, speaking thousands of languages, and most of  them are ruled by idiots and thieves.
I do have another theory, which I’m pretty  sure I’ve written about here at some point, but I don’t remember when.  It’s that aliens, being literal light years ahead of us in propulsion and life support technology, are probably somewhat more advance than us in inter-species psychology.  They look at the world, and see that humans are the dominant species, but how many species of human do they see?  One.  They will know a bit about evolution, they will be able to postulate the existence of Neanderthals, Denisovans, Homo Florensis, and others.  They will put two  and two  together and say:  These are people  that kill their rivals.  If they leave their system and spread throughout the galaxy, they will be a scourge on all civilized peoples.
Leave them be.  Perhaps they’ll self-destruct.