NB. "The reader" is a figure of speech refering to the reader who is reading the comment, whomever that may be. The point of the comment is that "repetition" is probably not an adequate explanation for flagging. Unless readers are informed who is flaggging and for what purpose, then all anyone can do is guess. No one knows why stories are flagged except the people who flag them.
Whether some HN practice has always been the case or whether it will remain so for all time is irrelevant. What's relevant is that aggressive flagging is happening now. Commenters share their thoughts about it. Some disagree. Some agree. Discussion continues.
The point of the comment is that "repetition" is probably not an adequate explanation for flagging. [...] What's relevant is that aggressive flagging is happening now.
Why not? Why does only the flagging need to be explained but not, say, the aggressive reposting of stories that are typically, and by long-established practice, offtopic for HN? These are clearly two sides of the same phenomenon, it's not obvious that the flagging alone here should be treated as some sort of anomaly.