I may understand “opinionated” differently from you, but the main issue is that when you do want to change something, you can’t. Or it’s some unsupported hack, or (best case) you flip some hidden configuration variable (that will probably break with the next release).
KDE is well configured from the get go as well, you don’t have to change anything and it will work well. But if you do decide that you don’t like some of their defaults, you can tweak many aspects of it.
Also, this isn’t even compatible with copyright law in some countries. I.e here you can’t give up authorship at all; you can only grant an irrevocable, perpetual license (that might even prohibit you from distribution yourself and such) but you’ll always be able to say “I made this” no matter what their license says.