Never mind. I was under the impression that anyone bumps into this room (probably from Math Meta) might have negative impressions when seeing words like "blacklisted", which are in fact auto-generated by bot.
@XanderHenderson I just flagged a few questions/comments all related to a certain user. And judging from the (now corrected) serial downvoting on my posts, this user has probably serially downvoted several other users.