As a student I used a ton of warez software in the 90ies. As such, I didn't have any real prejudice back then, and photoshop was the worst of the bunch from my perspective. I held that view for a long time, akin to how I consider autocad from autodesk one of the worst cads you could use despite being outrageously popular.

I have no longer an opinion on it as I didn't use it for such a long time. I'm cycling between krita and GIMP, and GIMP's UI is just fine to me, in the same way I suppose a ton of designers-with-big-opinions are more familiar with photoshop due to all the training they did on it (and probably, _mostly_ on it).