Also, while other locations in the Fediverse might disable access to unauthenticated persons, comments and post in Lemmy are generally public in that way. So, a blocked user could simply logout (or visit from a different instance) to see the content.
Also, as a third-party I do want someone (e.g. a fact checker) to be able reply to a comment with more information, so that I can see it, even if the commenter doesn't want to see replies (from the "woke mob" or wikipedians, e.g.).
I understand some people think the reply thread under their comments is somehow "owned" and should be "controlled" by them, but I don't agree. I think this should also be true in most places on the Fediverse, tho it isn't (as I understand it) on Mastodon (and the like).
I wish we had time-limited blocks / mutes on Lemmy. I use them all the time on Mastodon to exit a conversation when I am getting to short. If it really matters, I can revisit after a fortnight of reflection.