I'm willing to bet it all has to do with the sport/activity reaching a certain level of popularity. The moment something becomes mainstream enough, the toxicity creeps in. When it's a little bit unknown and there's a tight community, it's usually the best thing ever. When a chain of retail stores opens in every major town selling the gear then watch out.
Experienced it to a certain degree with MTB. Started off as a way to feel like a kid riding my bike again but certain people find a way to suck the joy out of it for everyone. That being said, there are a lot of nice people in that game but seems it only takes one to affect a day out.
Ocean Kayak fishing, when I get to do it, seems to still be in the sweet spot. Where I go is a more off the beaten track and so I don't get to experience the masses and the egos.