Snide and subjective comments aside, you’ve clearly missed their point.
Even if you take away subjective opinions on Liquid Glass, the point is that the core system updates things across the board.
Unless apps have implemented custom drawing, you get a consistent-ish UI (for better or worse) across the system, whereas with windows you are beholden to whatever hodge podge of UI frameworks were chosen at the given time.
That's a bad thing. It breaks apps. Apple has decided to stop supporting apps that aren't continually updated. Microsoft hasn't.
The size and losition of the traffic lights control is not dependent of the os the app runs on but on the os the app was compiled on. So things are not updated across the board