Just like mockery of gun owning, trump supporting, non college educated people from the midwest is bad, because I see you do enjoy that. Look, vegans/vegetarians annoy most people not because of their personal choices but because of the behavior and that makes them a target of ridicule.
Compare it to other people. Let’s compare them to the LGBT community. I think it comes down to public vs private behavior and overall goals. The wife and I have a gay couple who are very close friends, they regularly stay at our home when visiting and we vacation together, we attended each other’s weddings and respect each others relationships. We also have a vegetarian couple of similar closeness. The difference is the gay couple do their thing in private, they only ask for acceptance. Their happiness does not require we act like them, just that we accept them. The vegetarian couple need us and others to eat like them otherwise their sacrifice is for not. Plus dining is social, sex is private, so I get it that the vegetarians are more likely to lecture and try to recruit. I’m golfing with the vegetarian friend Saturday, and rest assured I’ll be teasing him. I especially focus on the years he ate seafood because it wasn’t cuddly, species bias is an easy target, but mostly because all his beliefs and habits are forced on him by his wife, another easy target. But he will draw first blood, mentioning something about my breakfast burrito from the clubhouse and my arteries or the treatment of the pig that ended up as bacon. Somehow the gay guys do not lecture me about their dislike of the female genitalia and my fondness for it. Some vegans lack mutual acceptance, hence the mockery.
AOC was a poor choice of examples, she deserves all the mockery she gets and then some. She spends all her days criticizing others especially those who disagree with her, so she is more than just fair game, she is mandatory mockery. I don’t spend my time telling everyone they can’t have a man-bun, but once someone says anyone who doesn’t have a man-bun is bad, that’s when I will use my superpowers for evil.