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.