Earlier quoted context omitted.
Compare KDE's Dolphin with Windows's Explorer (tabs, split view, dark theme a decade ago, file size/mod date under filename...) Ten Dutch guys can make for free a better piece of software than a multi-billion dollar corporation can because better UX isn't profitable when you've already captured 99% of the market. :p
KDE is not relevant or even heard of aside from people on Arch forums and more isolated communities. Heck the rare times I've seen Linux in the wild, guess what DE they were using? It's the one that's actually used by mainstream Linux distros, and even outside of GNOME, I even saw a wild Ubuntu terminal running Unity about a week ago. KDE should stop assisting with fragmenting Linux, or get the DE up-to-par for mains…
Honestly, it's better than GNOME at being an alternative to Windows UX, so calling them out for fragmenting Linux is kind of moot.