Best analogue I've heard is to think of it like email. Google can run Gmail, Microsoft can run Hotmail, and countless others can run their own email setups and everyone talks to each other just fine.
The fediverse is the same. Lemmy is made from a bunch of randos running their own Lemmy servers, but we all interact like it's one big Reddit-clone.
I'm convinced that some of the toxicity is tuned to your own contributions. I'm almost 40 and I still play League 8-10 hours a week.
Almost all of that is tipsy ARAM games, and considering I got my toxicity out years ago I find that, given I'm always positive and having a fun time, I solely run into others that are positive and having a fun time.
People might underestimate how much self sorting that game does based on behavior in their algorithms.
I was wondering the same thing