> Is liquid glass really that bad?

No, but every release of MacOS has a noisy minority declaring it, or some features of it, as the end of Macs. Some people will genuinely hate it in the way that nothing can be universally loved, some people will abandon Macs over it, most people don't feel strongly about it at all.

Maybe there's some people out there that love it, even.

I can barely tell the difference between the Mac I use that's been upgraded, and the Mac that hasn't due to its age, because I'm not spending my time at the computers staring at the decor. The contents of the application windows is the same.