> I don't understand why they wouldn't try to further liberate the phone that already runs an FSF-endorsed operating system, Librem 5. Perhaps one argument is to support more phones - but instead they could demonstrate a proof of concept for the most free phone, which is what I would expect from the FSF.

A cynical take would be that they're trying to sabotage the concept so it's unusable for non-techies.

A slightly more realistic take is that having their own phone is better PR than supporting someone else's, even if it is just a custom Android ROM instead of an actual Linux distro.