So GIMP has a larger user base than Blender, what is your point ?

I don't know what it has to do with anything - GIMP has been around for a while and has been the de facto FOSS alternative for photoshop for so long. That doesn't make that several of its UX and UI decisions are at least questionable nor make that comment you're replying any less true.

Not to mention the fact that if you ever mention in any way that GIMP's UX/UI could be better to anyone of its veteran devs they would turn weirdly ultra defensive and take everything personal.

Blender is something routinely recommend by normies. Gimp is not.

Blender is a very popular, maybe the most popular, for the tasks its used for. Gimp is not.

Market share might be more relevant when we're comparing products with different market sizes.