As opposed to us smarter people making cattle feed that contains cow brains, thereby propagating mad cow disease, then killing ourselves by eating them (Creutzfeldt-Jakob disease)!
Or for that matter killing ourselves in dozens of other ways due to lack of scientific knowledge, or ignoring it.
We didn't keep contracting mad cow disease until everyone who wasn't genetically immune to it died. I'm pretty sure we figured it out and killed loads of cattle to stop us getting it.
OK, but generations of people keep drinking themselves to death.
Generations of people lived with lead water pipes and asbestos roofs.
Within living memory we had cocaine in coke, heroin in cough remedies and were giving pregnant women thalidomide for morning sickness.
Western science is a modern thing, and even now many people don't believe it.