The fact that when you live in one place for a long time you get pretty fucking good at dealing with the pathogens there and when you evolve later you usually keep those defenses.
It’s more accurate to think of them as irrational beings with brain disease making them unable to think clearly. They have vague intuitions and a complete inability to think rationally.
So basically the immune system just kind of sucks? I mean trees don’t have one and they’re fine so I guess it’s just supplementary and not that effective compared to other things?
None of that should matter if you have and use a brain.