...of course, if *you* choose to not see replies from poster X, and thereby miss a reply to your question, that is only on your head, self-inflicted. We'll assume you are an adult, making adult choices, and we get to point and laugh.

Yeah, killfiles ought to be used sparingly...but there are times where someone has demonstrated a persistent cluelessness such that you are willing to risk missing a useful reply from that person to avoid seeing all the crap.