It's the same reason he gets big mad about sports or other states, or other cities in his state. Lou is a very "tribal" person, he wants to be part of a group, because that way he can exercise his viciousness and cruelty knowing he has allies. You see that everywhere (and very commonly in cows), some people want to belong to a group not to have friends and like-minded people to share their lives with, but to have a platform to attack others. That's why you see a lot of extremists of one political stripe change factions to another a lot more than moderates (lots of Alt-Righters are ex-Communists and vice-versa, for example), they don't pick sides based on whether they agree with the "in" group's ideas or values, they pick sides to have an enemy to attack - most extremists agree much more on what they hate than what they believe in.
By being part of the "correct" group, Lou and people like him can bully, abuse, defame or use violence against the "bad guys" with impunity. They often don't have a clue what their side believes, or what the other side believes, they just want a group of people they can dehumanise and persecute. You see this in Lou's massive hypocrisy, he will do and be all the things he accuses the other side of. That's because he doesn't really understand or believe in things like not deadnaming people, not using slurs, not attacking people for their disabilities, he just wants an excuse to abuse people.
See also Moviebob - "No bad tactics, only bad targets".