Some video editors like Shotcut, Flowblade or Openshot are not affiliated with any particular platform, so you cannot evaluate them based on platforms. But Kdenlive and Pitivi are associated to specific Desktop environments and technologies. I am asking us to evaluate platforms based on their software. Lets evaluate KDE and Gnome based on what they have to offer?
You're asking the wrong question. Maybe you are new to all this Linux stuff, but you can run KDE software under GNOME and vice versa, this is extremely common. Pick which ever DE you like the most by itself, and independently pick the editing software you like the most.
Bro desktop environments don't have video editors. That's why they're desktop environments. KDE is a open source software community. They make a video editor called kdenlive. They also make a desktop environment called Plasma. These two things have nothing to do with each other.
I feel like everybody got it so serious. I got it as a which one would you choose.
Last time I had to edit something I used olive. Didn't got in my way to get work done. So, I liked it. Olive uses QT instead if GTK. But I use gnome as my DE for some years. I try something else time to time but always get back to gnome.
So between these two, that there are many years I don't try. Just by the picture. I would choose piviti. Qt things use to have way more preferences visibe at once, qt apps looks more advanced tools. Some times this may add noise to get to the few important things/ui elements buttons to get the work done. But my experience with Olive and Mixx that are both QT were really good. Maybe I should try KDE again.