I used to think this until I met an acidhead who would dose every weekend. Most racist person I've ever met and, if anything, the acid made him more racist.
Agree with your premise, but supply chains for all food are horrendous. Leafy greens are the food that are most likely to give someone food poisoning, although the diseases are usually animal waste-borne.
Because it's easy to pull a trigger to permanently silence people who might become a slight inconvenience at most.