Long time geek, fangirl, mother, and reader. I've got a lot to say, you might not like it all, but it will be honest and hopefully helpful.
"Revealing someone’s “real life” identity and location quickly came to be understood as a sin of great magnitude, whereas in the days of zines, such information was commonly shared."
This is not exactly true. I knew many people who both distributed and subscribed to zines using PO Boxes and nicknames. I had penpals I only ever knew by their fandom names.
Not that this fact matters, because this is about characterizing the old school fanzine version of fandom as more intimate and personal, and modern, internet based fandoms as huge and impersonal.
Which ignores how the internet gave a wider range of people greater access to media and it's associate fandoms. Many people who either had no exposure to the media and/or fandoms in the first place, or people who didn't have the ability to participate, whether the road blocks were economic, geographic or cultural.