I can't say how particularly American it is not having lived elsewhere but it's a silly but oft effective little tactic. Taking the long view it goes all the way back to Andrew Jackson. In modern times it can be traced back to people like Nixon, Agnew and George Wallace. There is a mild belief, probably shared by many Americans regardless of political affiliation that college is not the only or even always the best way of obtaining useful knowledge. College grads, after all do a lot of stupid things.

Politicians often attempt to appeal to this and pander to darker impulses of resentment and ideas about "real masculinity" and so on by pretending that they stand with the "real Americans" against those (presumably effete) "egghead liberals" or "college grads that think they're so smart". Ironically, without fail, the people that talk like this are college grads and often like Santorum grad school or professional school grads as well. Heck, both movie versions of "Straw Dogs" touched on this trope.