Amateur philosopher here:

What is the debate going on here? Is it epistemology? Or linguistics?

I imagine its some subset, if anyone can point me in the right direction, I'm interested.

It's trying to maintain definitions of things we love that are resistant to being lumped in with commercial parties, and hold the things we love about them as an important distinction.

When I think "rave" I don't think about paying stupid money for drinks, being groped by security, mainstream artists and EDM ("musical gentrification") in general, curfews, expensive tickets, arbitrary rules, profiteering, or drugs/sexual expression being frowned on or barred.

Raves should be counter-culture, anti-authoritarian, DIY, and anarchic. Bona-fide liberated situations that aren't behest of the rules and requirements of commercial events. This is a definition that shouldn't be diluted nor conflated.

Neither. It's definitional and/or historical.

I always wondered how they got enough power into abandoned places.

they bring generators! There’s a surprising amount of planning and logistics involved, even for sketchy seeming events