Humans definitely rely on parasitism to survive, especially on each other, but we're susceptible to intra-species parasitism because our organizational instincts lead us to be credulous. I think if we didn't think of it as that, and embraced a cooperative outlook (that restricted competition or antagonism) then we'd have fewer people wanting to engage in parasitism.

But I'm guessing. Some people want to compete for competition's sake, and some people do so just because kinder survival strategies aren't available or working.

That said, whether we go extinct in the next few centuries (a significant risk right now) or we are able to organize enough to quell the climate crisis and clean up the plastic crisis, or just are reduced down to thousands, and stay that way though a few ice ages, is beyond our individual power to influence at this point. Our elites who own all the wealth can't even think past next year, which might be an indictment regarding the deep-time survivability of our species.

I've learned to disinvest. I will not be here to notice what happens, and have only been disappointed in how humanity treats each other.