Why not, exactly? I think with the way the fediverse works, this would be a needless hassle for them to program this in. IIRC, posts are all separate and are just referring to another post. I think it’ll be up to their server on whether or not to honour that block (your server could possibly sever the link on it’s frontend, but that won’t change that the person linked your post to theirs)

And even if you could, they could still post a screenshot locally or write stuff about you.