Nobody I have seen has claimed rube is STUPID..
Oh, well then let me be the first.
In the more than a decade that I read rube's posts, I never read one; not a single one...that suggested to me that he possessed anything other than the most mediocre of intellects.
And I'm not just talking here about his obvious complete inability to interact with other human beings in even a minimally effective way. It's possible to be an intelligent person and still be a social retard; I've known some very intelligent people who had little to no interpersonal skills.
And nor am I just talking about someone with whom I disagree on just about everything; there are a number of folks here who would fall into that category, and I have nothing but respect for their intellectual abilities, (Merely being wrong doesn't make one stupid. Smart people reach the wrong conclusions all the time.

)
No, I'm talking about a supposed "scientist" who apparently finds himself deeply challenged trying to interpret simple charts, tables and graphs. (On numerous occasions, he would reference one of these that in no way demonstrated what he claimed they did; the obvious explanation for this is that he didn't know how to read them correctly)
I'm talking about a self proclaimed "inventor" who has almost
never expressed an original thought, and who has openly
bragged about being "predictable". 90% of what rube has posted has been copy and paste jobs, and most of the rest consists either of smarmy and or/juvenile insults, or assertions that bespeak a profound ignorance of the subject matter, (like, "there was no genocide before Christianity", "the Catholics don't value education" and "Rousseau was a reactionary")
This sort of behavior is evidence of both intellectual laziness and a lack of intellectual curiosity. Qualities not generally considered to be the hall marks of an intelligent person.
I have seen nothing that suggests to me that rube possesses a level of native intelligence any greater than that of quaddriver, for example. In fact they have one major characteristic in common; the complete disconnect between their perception of their character, knowledge and intelligence, and the evidence of it.