It’s why as a UX designer I don’t contribute to open source projects any more as the fight just isn’t worth it.
GIMP is peak that attitude. It could be a top-quality mainstream open source image editor if they wanted it to, but they don’t.
Photopea is the work of one guy, Affinity Photo was made by a small team, so it’s clear it’s not manpower but attitude.
They’ve got things just how they like it and the last thing they want is to make things easier and have a bunch of n00bs running around and spoiling things, thank you very much.