You realize life is complex enough that two things can be true, right? That everything isn't either/or?

The reason we've haven't had more outbreaks of more diseases in the last century is because we had a lot of smart vigilant well-resourced people who very much felt the disease was the problem, and took steps to mitigate.

Classic late-stage civilization blunder is taking the fruits of civilization for granted. Sorry you're not aware of those things, but that's on you.