That's always been my theory. He's been complaining about IQ tests for a long time, even before the "it's racist" SJW bullshit. Considering how he was as a teen (And is now) you just know he's one of those guys who thought he'd score a 200. But then he actually took the test, scored below 100 and was told how bad that was, and now is insistent that it's worthless simply because he didn't get the answer he wanted.
I don't think he got as low as 80, I knew a guy growing up who was in the 80s and Bob isn't as slow as that guy. But if it was the low 90s? Say 93, that'd make sense to me. There have been people who analyzed Einstein's speech and work, same with Stephen Hawking, and were able to place their IQs in the 160s, could anyone do that for Bob?
Most likely, Robert has this weird hang up on being "smart" and how he sees himself.
Whenever the topic of intelligence comes around either he boasts himself with the typical "I'm smart, but unfocused" or the humblebrag "I'm just a dumb mediocre guy, but even that puts me ahead 80% of americans, that is just how DUMB this country is

"
Or Robert likes to use qualifiers, as in "there are a lot of types of intelligence, like emotional one" when he wants to dump on IQ tests and all that.
Not to mention in Robert's book he was quick to justify his poor academic grades as being "difficult" and "prone against authority", yeah sure Robert, whatever you C- bitch.
But here is the thing, when you reach adulthood, you stop caring about "intelligence".
I mean sure, we can compliment and talk about how so and so are smart and knowledgeable, and cool, that kid is so bright he can do rubik cubes with his buttcheeks, but usually we tend to just compliment "smarts" to children, who are still young and naive enough to give a shit about grades and quantifiers to intelligence.
But in the adult world, there is only one measure, what can you do and what have you acomplished? No ones gives a fuck if you have a 200 IQ, what grades or degrees you got if you have squat to show. And we have reached the crux of the issue here for Robert.
He doesn't have anything to show.
Robert, who grew up thinking of himself to be ahead of the herd, found out that in the adult life whatever "intellegence" he perceived to have, didn't magically grant the life and sucess he thinks he is deserves. He found some niche audience on a gaming site and somehow thought he would be just a few years away from a phone call to write the script for the next "geek propriety" blockbuster.
When that didn't happen, well, we can see the cope on those not so passive-agressive tweets he rolls around, as in the is smarter than most of his peers, but he didn't have the money to go to ivy league colleges. or he laments being so smart, but unmotivated, as if it is a curse. Or sometimes he straight up blames others, like the "alt-right" youtubers who destroyed film discourse on youtube and now the algorithm won't grace Robert with views on his amateur videos.
So, with that, Robert has to retreat to "intelligence", as a maleable concept as it can be, but Robert has to believe he is, indeed, smart, because being "smart" is all he has, even if we already stablished, no one gives a shit on how smart you are in the real world, only what you managed to do with your life.