I've always assumed that when a story rapidly drops past the first three pages (e.g. >90) it is because it has been flagged some indicative, disproportionate number of times[1] by users with flag functionality. The submission seems to presume that such drops are only the result of Daniel or whoever manually doing it.
Which is true?
[1] - Notably the majority of the "removed" stories have pretty tiny number of upvotes, so if flags are weighted proportionately it wouldn't take many.