Why do some people say "I wouldn't want a government to dictate what I eat"? This would mean they'd be against food safety regulations, would it not? Context was the idea of a government banning meat

Most people who say that do so for dogmatic reasons, not because they arrived at this conclusion after careful analysis. It's the political point of small government.

These are the same people who will probably be first in line shouting for government intervention when their drinking water is full of chemical waste.

You can try to reason with folks like that but you probably won't change their mind. Just try not to shout at them.