Ah, but see, if that person (let's say A) is in conversation with a person who has blocked you (B), well, by most social conventions you would not invited to that conversation. The online, asynchronous nature of the forum means that you still have access to a portion of the conversation, but a percentage of a thing, no matter what the skew or balance, is not that thing, and engaging with that conversation necessarily means engaging with all of its participants, Even the ones who have you blocked. And if you're finding engaging with the conversation difficult because you're missing important context, context that has been purposefully blocked to you, then by looking up that context you are necessarily engaging with them, even if you aren't directly replying to them.