Can you give examples of absolutely moronic NTs from fiction?
INTJ - I remember thinking the guy from Men Who Stare at Goats was a deluded INTJ, but I was half asleep watching that movie, so I could be way off.
INTP - Many people type Neville Longbottom as an INTP, though I'm not sure
ENTP - I think these are fairly common as the clueless but energetic ideas person, like Mr Bean (though with the things he comes up with, he's arguably smart)
That's all I can think of at the moment.