Yeah casual guilds don't really have those issues because the requirements for skill at low raid tiers are so lax. Honestly the game kinda lends itself to toxicity when you play in 25-man groups, and it only takes a single person messing up in a mythic raid to ruin the pull for everyone. When it's like that, isolating the "problem" player is going to be pretty common, and people tend to be more elitist and toxic in general when they are hiding behind a computer screen.

That's not to say a high level guild can't be positive and supportive, though. One of the things I like about watching RWF is that most of the high level guilds seem to have such a tight bond, and they never point fingers over a single raid wipe. They're all in it together and come up with ways to compensate for each other's weaknesses. But it probably helps that every player is highly invested in playing absolutely perfectly, and I'm sure getting a guild to that point requires aggressively cutting out a lot of weak links along the way 😐