There are two interesting things here: First, there is evidence that Cantor really did do worse in heavily Democratic precincts. But the relationship is weak, and doesn’t come close to explaining his loss. Moreover, we don’t know it was Democratic voting in these precincts that did Cantor in. It might be something about Republicans in these precincts that caused them to dislike Cantor more; in other words, we might have insufficient controls in place.
Second, the second regression equation in particular is consistent with the “home style” hypothesis from yesterday. Cantor did well in the D.C. exurbs and in his old base in the City of Richmond. He did poorly in exurban Richmond counties, where he was less of a fixture.