Just a couple of friendly suggestions that might help user awareness:
- When someone is added to an ignore list, let the ignored party know with a notification. That would eliminate awkward conversational interactions and allow them to know if they are not able to be seen.
- An optional link to the post that led the person to ignore them - so they at least know why - This might help them be more aware of the kind of comment that causes them to be ignored and may (or may not) encourage them to not make such comments in the future.