Read again what you quoted, please, and then point out where did I say devs shouldn't have the right to decide features. I clearly stated it's good to have it as an option (for example, if I understood correctly, Qt handles it with a switch to enable CSD on your app). Forcing CSD means you have no decoration by default, and your example is a corner case, and someone actually taking the time to design something as superfluous (on most cases) as the decorations is not really common, and something most try to avoid.
CSD is like prometheus' fire, yes. We can make good or bad of it. The nice part is we decide. Respecting HIGs, Theming and design guidelines are a good way to do it, Gnome proved this. KDE could do this too, it is really not that hard. Or are you saying that app developers shouldn't have the right to decide and features must be done away with? That is sweet irony, I think. Gnome wants flexibility and features, KDE wants to be locked down.
Qt's "write once, deploy everywhere" should not be allowed to stop us from making the best possible Linux desktop AND reducing complexity. KDE can find other ways to make the same code behave differently.