Humans are sorta the top of the food chain, though stick them alone against a lion or other great cat and humans make a tasty meal. Humans also make great incubators for tiny things as well.
I've always been fascinated by the myth of the self made person. I've never met one who actually was. They were the result of a lot of different people's efforts, beginning with pop squirting it in and mom squirting them out, but were incapable of, or unwilling to, acknowledging that part of their story. And there are the tens of thousands of individuals tangentially involved in just that one birthing event, not to mention all of the thousands of events since.
I don't disagree that there are a fair amount of parasites in the population. I've met thousands of them over my lifetime. Problem is, we largely venerate our parasites.
A lot of us would rather be Mr Potter than George Bailey, and in our devotion to self centeredness, would rather be Cain than Abel.