Yeah, its infuriating that punk has become a suffix.
There is nothing punk about steampunk, dieselpunk, atompunk. They are just fantasy technological scenarios / art styles.
Cyberpunk has an both a recognizable aesthetic and a whole lot of political, social and philosophical views baked into it. You get the punks in cyberpunk as either a direct ideological opposition to the power of corporations, or as an indirect result of said corpos creating a hell world for 99% of people.
There is nothing inherently rebellious about worlds or characters within worlds with more prevalent / advanced steam or diesel or nuclear power.
Solarpunk arguably has some actual punk to it if you actually try to follow the idea of personally minimizing your fossil fuel usage, but mostly its a utopian or post-dystopian setting / art style.
Its now like -gate being affixed to any kind of publicized controversy.
Most people do not understand what Watergate even was and why it was so significant.