i've started to see the block feature as "can i trust this person to talk to other people in my comments?"
if the answer is no, it doesn't matter if whatever you said was directed to me or not
I used to avoid using the block feature largely because people can still respond to your threads as long as they reply to someone else's comment. They can even still have you as one of the people that are tagged. I mostly use it simply to communicate I want people to leave me be.
The way they've implemented blocking is as helpful to people being abusive as the ones they're targeting. If you block them, you can't see they're responding in your thread in order to hide their messages. They can also block you to stop you hiding their replies in your thread.