I did a search to see if anyone else had brought this up here because I've just noticed it too. It feels like an oversight to me. I don't know if I can think of a situation where you'd block someone and still want to see notifications from them. Silencing and blocking someone at the same time works, but it does feel like kind of an extra step and not what you would intuitively expect
oh yeah this is a weird one, personally I think of block as "stop this person from contacting me", I suppose because I think of blocking phone numbers as the original definition of block. I don't put too much value in "don't show this person I exist" because it's not immune to new accounts or logged-off use. At the very least this distinction could be communicated better. Maybe if you click block, pop up a confirmation dialogue:
Are you sure?
This person will no longer see your posts or comments.
(checkbox) Also don't show me their posts or comments.
Very weird that this isn't the case.