The description you posted states that ESFP's tend to avoid theoretical thinking, and don't like classroom learning which says nothing about inborn intellectual ability. The IQ test that a lot of people here tend to refer to is about ability to learn, adjust to different scenarios and problems, and have the ability to solve those problems. There's no "deep" philosophical thinking involved, only quick and simple problem solving. So, one can be a stereotypical ESFP- someone who hates school, scoffs at the idea of opening a philosophy or physics book, and just wants to just go to the beach all day long and still have those adjusting and problem solving abilities (greater than that of any stereotypical INTJ,). Smart ESFP's can dance cicles around schools, never show up for class, spend all night partying and still get straight A's.(Because if you're intelligent, you've probably found out how to do so. ) It's not an ESFP's perogative to hang around with books, they want to be around people and excitement. That's what the description is saying. You can keep your nose in a book all day but inborn intelligence is inborn intelligence, it's not changing. "ESFP's don't like to theorize so they are dumb" is just a wall to hide behind so that some of you can say... "Well I like to theorize! I like going to class. That's something I can do all day to avoid life experience. That must make me smart, unlike an ESFP." Think again. I'd like to see half of you sitting next to my empty seat in class, (or doodling and snoozing self) and take bets about who's going to get the better grade. I'm pretty sure that most of my former classmates would have still put their money on me.
ESFP's hate school, books, and theorizing. Intelligence is a whole other thing.