The comments on this question were recently purged - but only partially.
Some of the subsequent comments devolved into Q&A, so I understand why some of them may have been purged.
But others of those comments were direct responses to the first comment that weren't questions, but were clarifications to that initial comment that (IMO) were essential.
This Meta answer suggests that comments are not intended to be permanent, and that they tend to be opinion-based. But none of that explains why a partial purge might happen.
What's the cultural/conventional/policy reason that the initial comment survived, while all subsequent comments got purged?