many vegetarians and vegans are such because they believe that they will affect the market and stop the bad practices of the bad farmers of meat and animal products.

let's change up the subjects and see if the logic still makes sense:

butter is partially oxidised milk fat, people are getting less quality oils and vitamins out of their milk by doing this. let's boycott butter so that dairy manufacturers skim less cream off to make butter.

does that sound like it's gonna have much effect, even if it reduces the business of butter churning by 20%?

what this logic forgets is that they are going to look for the cheapest way to retarget their product. avoiding meat products just resulted in a tiny bit more grain production, and then they fed the grain to the cows instead, making the meat product even worse and enabled more feedlot cruelty.

at least, for sure part of the result of the "vote with your dollar" tactic of vegetarians.

if they were more sane, they'd be buying up all the organic meat and milk instead.

the "vote with the dollar" idea is weak because of the complexity of production, and that's also why it was promoted by the owners of food megacorps, who have used these feeble minded people to usher in ever more vicious quality reduction of the product, and increased the cruelty level.