Well, this was extremely disappointing. Only one person had a helpful reply, pointing to this link explaining the basics, a couple others vaguely gestured about their distaste of Meta, and everyone else demonstrated an even lesser understanding of the fediverse than I had started with. One particular flat-earther just called me a slag and posted a screenshot of themselves downvoting all my comments.

What? Let me guess, you’re a flat earther too?

You can’t block anything from seeing your posts and comments though. That is point of a free and public space. Defederation isn’t doing what you think it is