I think it speaks to the heart of it. Please feel free to elaborate on why I'm wrong.
But here's how I understood it: He was exaggerating a bit for the purpose of making his argument a little more punchy, and phrases like "most of whom can't even swap a tire for a donut without calling AAA" are clearly meant to have an element of humor to them. You took his words at absolute face value without stopping to think that they might be meant as something else.
Its seems quite likely to be (insulting) hyperbole, but I don't see the humor. (I suppose it kind of sounds funny if you aren't used to the use of the term "donut" to refer to a reduce-size, limited-speed spare tire, since talking about swapping a tire for a donut would in that case be an absurdity.)
The problem I have with the GP is not the literal words (I have no problem with style), but that he's complaining of being stereotyped while spreading a stereotyped anti-intellectual message.
Taking this single little point and then using it to systematically reject the whole argument is an example of what the parent was ranting about.