I’m pretty sure an instance can have custom UI and there are mobile apps that look different too. But I remember being a Digg user 15 or so years ago and the main reason I didn’t switch to Reddit was that I hated the UI. Eventually I did switch as Digg started to die, but the UI really grew on me and I would much rather use that old Reddit UI than the new one.

My point is, I think they don’t like it because they’re just not used to it