I'm not sure Kronk is so much flat out stupid as pulling Obfuscating Stupidity combined with naivete. He does several things in the film that indicate he has decent brains -his problems fall more in not liking to make difficult moral decisions, not liking to kill, and turning a blind eye to just how nasty Yzma is until she personally insults him in a way he can't ignore.
Coming back to where you started is not the same as never leaving. -Terry Pratchett
I'm not sure Kronk is so much flat out stupid as pulling Obfuscating Stupidity combined with naivete. He does several things in the film that indicate he has decent brains -his problems fall more in not liking to make difficult moral decisions, not liking to kill, and turning a blind eye to just how nasty Yzma is until she personally insults him in a way he can't ignore.
Coming back to where you started is not the same as never leaving. -Terry Pratchett