It's probably a coincidence. 155 users were deleted and 46 destroyed by moderators, but that doesn't include self-deletions. I don't know of any way to get specific numbers of how many users delete their own accounts, but as far as I can tell it accounts for the bulk of overall account deletion. In your specific case, as far as I can tell only 1 of the 5 was deleted by a moderator.
I won't go into specific numbers, but if anything December was a slow month as far as moderation is concerned. Certainly there wasn't an end of the year clean up on our part.