De-emphasizing intellect is a far cry from pretending to be stupid. In fact, character matters at least as much as intelligence in real life. What use is intelligence if you don't have the character to execute when you have to do something hard? And of course, ethics provide the end goals to which intelligence is applied.
So your contention is that character and ethics are exclusive of intelligence? If not, why would one need to feign stupidity in order to project character?
Not talking like an Ivy-league graduate isn't the same as pretending to be stupid. When you're around friends who don't understand computer science, do you talk in programming lingo? I assume no. Does that mean you're pretending to be stupid? Again, no.
Bush actively projected stupid. I say this as both an "ivy-league graduate" and as a rural (redneck) American: speak to people as yourself. Most people are not stupid, and pretending to be stupid to be more likeable is absurd. "Smart" is in no way equivalent to "programming lingo".