I can't believe that he is actually stupid (despite evidence to the contrary) but I do believe that his ego and insecurity make it impossible for him to slough off criticism.
Despite the fact that he is a complete political novice, Trump won't believe that anyone could possibly know more than him about politics. Real experts in the Republican party try to save him, and their party, by urging him to stay on message….but he ignores them and shoots off his mouth. I think that's stupid, really stupid.
ryck
"What Were Once Vices Are Now Habits" The Doobie Brothers