I’m sorry but I believe that the PR referenced in this thread is faulty:
This “feature” does not consider the fact that one might use Discourse as a SSO provider and users may not post in the forum but only use the main site! As this scenario is normal for my site I have lost about 70% of users on Discourse in the last months (which I just found out by coincidence)… creating quite a huge gap between the forum and the main site. It’s also normal for my site that users only post in the forum several years after they have decided to create an account to use features on the main site. Now those users cannot login or have to create a new account disconnected from their content on the main site.
I specifically migrated the users with “active: true” several years ago to prevent something like this.
Purge is also something the admin should actively decide on before turning such an option on in my opinion, at least for a already running Discourse forum…