Yes sadly that is very true. I was the original top mod for /r/StarTrek (I quit last year) and eventually realized I had to make our rules distinguish between "debate" and "arguing", between "constructive" and "un-constructive" speech. It's a difficult line to walk, but if a space makes room for arguing and low-effort bickering like that, it has a way of taking over every topic. Ultimately moderators have to tell people "It's OK to have an opinion but you need to express it constructively and explain why you hold it if you wish to participate".

Same goes for mindless cheerleading too honestly, though it's not quite as toxic. But left unchecked, internet fandoms have a way of dividing into ideological camps with purity standards. I encouraged my mods to maintain a "house party" atmosphere. Let people do their thing, get silly, have drunken debates, etc. But if you see someone acting inappropriately or making it not fun for someone else, time to put on your party host hat and ask them to leave. "You don't have to go home but you can't stay here".