There have indeed been bad experiences in the past with attempting to purge
archived emails, and even if purges could be done cleanly on the public
archives, the action would not remove the content from the automatic 3rd
party archivers and the subscribed email accounts. It would be nice to have
a solution to this kind of situation, and I hope that WMF will find one or
make one.
Thanks to everyone who has or is working helpfully to address today's
incident and related issues.
Pine