That's rich, coming from a project very closely tied to Gtk, which has a history of massive breaking changes, and outright removing functionality, leading to many projects continuing to use older versions of gtk for a very long time.
I believe they mainly remove functionality between major releases of GTK, not within a release. Can you cite an example where they have done this between gtk minor releases ? Aka gtk 3.1 -> 3.2 ?
Fedora KDE is literally release blocking and has been approved for promotion to be on the same level as Fedora Workstation.
Red Hat isn't as involved with Qt, which is mainly maintained by yhe Qt group company.
RedHat employees make the majority of commits to Gtk and I think are some of the maintainers/managers?