@dan A blog is not ‘social’ media. You usually own your blog and can set the rules to it. “I post to public USENET groups/IRC channels, but no replies allowed” would be a more apt comparison. Using social media and then refusing to socialise is the very definition of defeating its purpose.
Of course, you're entitled to block/mute anyone who replies to you if you're so inclined. What you can't do is disallow them from replying. To think that you can is childish and, quite frankly, stupid.
Anyway, was your post inspired by something that happened or just a hypothetical?
One big difference between online and analogue social spaces is that "parasocial" relationships are much more prevalent in online spaces, and our platforms need the tools to manage them.
> “I post to public USENET groups/IRC channels, but no replies allowed” would be a more apt comparison.
Supposing that I'd created the group or the channel for that purpose (and that this had been done in accordance with the rest of the server ops/news admins) then I can't see a problem here. Usenet has moderated groups, irc has chanops/voices ...