Some people take it way too seriously and end up alienating potential audiences.
Just look at Rick and morty. It’s a decent comedy if you’re into crass humor. I’ll admit I have seen most seasons. But you’ll never see me wearing merch because I simply don’t want to be associated with the crowd who scream at fast food employees over meme sauce. I happily wear my live long and prosper shirt or the Mando shorts my wife bought me though.
Some fandoms just take a little more digging to find the super shitty people.