Well yeah, what's the point of having rules on an instance if you can just break them by moving to another but still participate?

If your users post hate speech, child porn or run amok reply guying, then yes your likely to not federate with other instances.

For other differing rules, instaces generally silence from the federated timeline. Eg: I can still follow Humblr.social and Sinblr users, but Federated timeline users won't have to drown in porn if the admin silences the server.

Your server will be isolated from some other servers, but it's actually pretty hard to isolate your instance so that you're completely alone in the fediverse.

I googled this, and was very very sorry that I did. Suffice it to say this terminology is specific to a subculture of people who dress up as animal mascots. Booping snoots apparently means touching the nose, I think? I also ran across something called “cub porn” and now I need a shower so hot it can melt glass.

Toots are posts. Boosting is reposting so your followers can see it. Instance owners can change the terms to whatever cutesy terms they want, so this example has boost replaced with boop and toot replace with toot.

Also this is a FINE example of why niche communities need unbiased online infrastructure. A casual google-searcher may judge them by whatever google's AI decides is representative of the group, and choose not to deal with them at all.