The nginx path seems to be a dead end.

New strategy: remove unnecessary accounts and pages. Steps involved:

1) Identify all accounts that have never edited. These are likely spam accounts. False positives are acceptable because normal pages are world readable.
2) Delete those accounts [1].
3) Identify all blocked accounts that have created 1 page + the relevant page. These are also likely spam accounts, blocked during the time we had to handle spam manually. False positives are unlikely, but I'd like to have someone look over this list first.
4) Delete those accounts and pages.
5) Identify accounts that have made 1 (or 2) edits to existing pages. These might be spam accounts or drive-by useful editors.
6) If the list of spammers is long enough to take action, delete the accounts and revert the edits while maintaining the integrity of the edit history.

[1] https://moinmo.in/HelpOnUserHandling#Removing_a_user_account