When I visit the #mastodon page of a #kbin or #lemmy user/community through a direct link or entering the url (as opposed to navigating to it manually on mastodon), I get taken to the kbin/lemmy instance instead. How can I prevent that?
You can’t. When you go to a different website you’re going to a different website.
That said, there was a recent post about a Firefox add-on that would redirect you to that post on your home instance if you happened to click or enter a URL. I don’t have that post saved so you may have to search for it.
This happens with any kbin/lemmy community/user. Mastodon seems to automatically redirect, I'm asking if I can turn that off somehow. If I go to a mastodon.social url, I expect to arrive at mastodon.social not kbin.social or lemmy.world.
As I understand it, that addon you're referring to would just redirect a lemmy.world link to kbin.social (aka my home instance) instead. Which isn't really what I'm looking for at all.