Well, I would disagree with that sentiment, in a couple of ways.
"-punk" is about rejection of the status quo - whatever it happens to be.
Cyberpunk is not punk just because it is anti-corporate. It is punk because it rejected the genre conventions of its day. It is a rejection of the hard scifi and Space Opera that preceded it, aiming for a more grounded, cynical, near-future dystopian corporate collective.
That grounded, near-future cynicism became a major influence on science fiction in the 80s, beyond cyberpunk itself. So, steampunk rejects that. It is about not the far future, or the near future, but an alternate past. It rejects the cynicism for more optimism, in which personal craftsmanship and effort are the focus, and individuals regularly make a difference. Steampunk frequently includes supernatural elements where the hard sci-fi, Space Opera, and cyberpunk before it largely rejected the spiritual.
And so on. The focus on esthetic really does all these genres an injustice.