There used to be so many fun online social experiment games. These games still exist, but they don't feel the same anymore.
One of the biggest games that I used to be big about was Your World of Text. This is basically an infinite text document that anybody can edit. If you're on the landing page (0,0), you will mostly see racist spam and stuff like that, but if you start scrolling out you will find actual humanity, and it's awesome. You will even find people leaving messages. People still occasionally message me on Discord about messages I left over 5 years ago. However, most other social experiment games haven't been like that.
For example, a recent popular one has been Human or Not?, a game where you're paired with either a random human or an AI, and you have to guess figure out if the other person is real or not in 2 minutes. It's fun when it works, but half the matches someone sends a link to a Discord server and then leaves. This is a common theme amongst these games.
Another one was cursors.io, which was shut down because there were too many advertisements. When you joined, you would instantly see bots writing out Discord server links and stuff like that. These bots would fill the servers, so you couldn't even play if you wanted to.
Not every social experiment has been like this. "This Website Will Self Destruct" (which self destructed) was actually quite normal, and you could tell, because a lot of people vented on it. That was nice, I guess.
The thing that confuses me is why people continue to spam. What type of person is joining a Discord server because they were forcefully advertised it? The only reason I can think to advertise a server is if it isn't yours and you want people to raid it (which is what people who hack popular Twitter accounts do).