If popular opinion is what leads to regulation, then how is it best to go about changing public opinion so more and more people are for regulating the meat and dairy industries?

There are vegan activists who expose things about those industries that aren’t public knowledge, and that seems to move public opinion to a degree, at least locally/regionally.

Right now regulating meat and dairy is a deeply unpopular opinion no matter which party you look at, at least in the US.