Eh, it is kinda watering down the original punk, as a term for what the original punk movements represented. But that’s language. No matter what a word starts out meaning, people can use it for something else. If that new use takes off, there’s nothing that can stop it other than people as a group ceasing that usage. Isn’t that cool? See what I did there?
Tbh though, once a word gets used a new way, and it spreads, it’s just as likely that the original usage fades away. Don’t forget that words like idiot and moron had a more clinical jargon usage originally.
Living languages love shifting. Humans are sort of like birds with words. We collect shiny ones and play with them.
The various _punks and _cores are just a current example of playing with words.
As far as disliking or resisting that kind of appropriation, it can be frustrating. Anyone that was a punk back in the day would likely sneer at some of the _punk iterations, possibly calling anyone using them a fascist (and if you’ve never seen the show The Young Ones, you really should just so you can see an early version of the caricatures of what punks, hippies, and such were. Real life punks and hippies were a much more diverse and interesting thing, but less funny).
My advice as a fellow old dude that knew some of the old school punks? Just shrug and smile. Change is inevitable, might as well just roll with it.