It was just the catch-all "we're reducing the personal data visible through our API". Nothing specific to the events API. Which would make sense if it restricted the ability to see how many people were going and who had RSVP'd, but they shut off everything.

When I asked Facebook support, they gave me two options: direct users to the Facebook Local app (bypassing my site), or have every business I wanted to collect event data from log into my site and store their user access token, and that would give me permission to collect their events. This token needs to be re-upped every so often, so now I'm asking hundreds of people to log into my site every month just to keep their events populating. Most of the business owners can barely use Facebook to begin with, it's just a non-starter.