I'm only on the periphery at the moment because I've been too busy with work and life to really dig in but, I'll try to answer from my perspective:

The concept of a public Unix box is neat, but why?

There are MANY "whys" here. I think some of it comes down to "information wants to be free". A pubnix is something of an internet "town square" where anyone can interact with Internet-connected information (including what other people write) without commercial pressures. Furthermore, it provides a place for people to learn how to interact with computers on a much lower level than is possible through browsers or the new walled gardens of social media and to enable preservation of old technologies and creation of new ones (see: Gopher and Gemini), again, without the commercial pressure that has caused so much rot in the worldwide web.

Is this a way to connect with like-minded people?

If one chooses, absolutely. There's text-based chats, Gopher access, quarterly Plan9 courses and more. But, one can just tinker on their own, if they like.

Is this locational?

Beyond latency, not really. I'm not aware of any limitations on membership outside of sanctioned countries.

I've known about this for a while and I don't really understand the purpose.

This is another wonderful thing. It doesn't NEED a purpose or to have a justification for its existence. It's quirky and a bit esoteric but, that's more than enough. Kinda like life, it's up to an individual to find purpose in it.

What is anonradio?

aNONRadio is a non-profit, non-commercial internet "radio" station, hosted by SDF.org members. The name is apparently a tribute to the Dallas-based KNON station, a nod to the NON-profit and NON-commercial nature, as well as a joke since it is an internet broadcast and no real radio-waves are harmed in its production.

~~Lipsy~~ Lispy Gopher show?

This is a weekly show on aNONRadio that focuses on the Lisp family of programming languages and the Gopher protocol. If you're not familiar with either, Lisp uses a lot of parentheses and a variant is at the core of EMACS (allowing a ludicrous amount of self-modification), and Gopher is a document-centric protocol, built on top of the Internet Protocol, that predates the WWW. A recent protocol that you might also come across is the Gopher-inspired Gemini, which was created with intentional lack of extensibility to attempt to avoid the unnecessary (and sometimes harmful) complexity of the WWW.

I have so many questions, I'd love some answers.

To answer the one that you may not know that you need to ask: : !unix_surrealism@lemmy.sdf.org is where to find Analog Nowhere, the greatest esoteric technology-themed comic universe that involves techno-mages and anthropomorphized unix-like OS mascots in the whole of the Fediverse.

For any other questions, ask away!