I do think it would be less bad if it only prevented direct comment replies, and not replies to top level posts or replies to other comments by other people further down the thread.
I don’t understand what you mean by it still occurs in the other direction though. Nobody can prevent people from commenting except moderators and admins, which is how it should be. Mute style blocking isn’t moderation because it doesn’t affect anyone’s ability to comment, it’s effectively the same as a client level filter.
I’ve blocked a bunch of people, who may be replying to me with harassing comments, but that isn’t influencing what I do. It might influence the overall conversation, and that could be a problem, but I think the way that problem is dealt with should be public, because the problem is public, it’s not something that’s exclusively my problem. I don’t think I should have the authority to act to police any arbitrary community like that, especially without anyone being able to know that I’m doing it.