so they wouldn’t break completely when installed on the “wrong” desktop
the kde apps are made theme agnostics specifically to not interfere with the way other desktops/distro want to theme them, and the gnome desktop is specifically made to not natively handle user themes so as to not interfere with the way apps are supposed to look like, mix that into a bowl and you get ugly kde apps, which one is in the wrong is for you to decide*^1^, but at the end of the day you need another app to handle your qt-theming since gnome doesn’t natively support it.