Anyone with a headset can enter, anyone can leave all the same. This leads to shitheads and dildos grouping together to socialize without identities, which leads to cancerous, no consequence interactions, which means no amount of learned civility, which means shitposting central.
You see, when you're talking with people face to face everyone hides their inner nature and projects a mask for the sake of building bridges, because the people around them are in contact with eachother, and thus cannot escape a notion about them once it's been set, which determines their dominance or role in a relationship with other people, and generally having people think ill of you is a great way to get alienated from a community you can't escape from.
Without identity and thus something that ties you without your choice, the inner self that you hide from others, your psychological shadow, will emerge and become what you present to other people.
This includes your inner perversions, your pathetic aspects, and your hobbies which may not be acceptable to the general public if you have them. Thus, crazy finds a community, hell breaks loose, and quality is not assured. And this cannot be controlled, so buckle up fucker because you either join the ride, make your own shit or stay the fuck away.
VRchat and the like are where people let out aspects they have suppressed and release their inhibitions in a safe environment. Asking people to be civil or to do quality work in such an enviroment is pure insanity, you can't expect people to act well when they have no scruples or things to restrain them.
Also remember supply and demand, if people want memes, then memes will be made, if people want quality then quality will be made. If you want quality, make quality. It's not hard to make and rig a model, it just takes a little work and some time. Hell you can download another model and make alterations if you don't want to do it from scratch, even the Ugandan Knuckles tribe does that shit themselves.