I wish there was some way to require meat eaters to at least visit a slaughterhouse every year to witness the animals that they eat getting slaughtered.

Even better would be if they had to slaughter some animals themselves rather than simply paying people to do it for them.

Farmers and slaughterhouse workers get desensitized to the slaughter of animals, but I suspect that if people didn't do it all the time but just, say, once or twice a year and saw what actually goes on in slaughterhouses most people would be horrified and many of them would turn vegetarian.

Even a single field trip to a slaughterhouse as a kid would probably make lifetime vegetarians out of a lot of people.

Most people don't want to think about what they're doing to animals (and certainly not witness, much less directly participate in it), though, so it would probably never happen.