College educated have not favoured the GOP in a long time overall, rather college educated whites did as usually the GOP wins the white vote by 10-20 points.  I suspect the reason college educated whites historically went GOP was income since the GOP is more likely to cut their taxes so probably economic rather than social concerns were the reason.  I know myself some in the top 1% who hated Harper and were planning to vote for Trudeau, but when he promised to raise the top rate by 4% they swung back to Harper so probably same thing here.  Otherwise mainly self-interest not necessarily cultural agreement.  Also amongst whites GOP runs up massive margins in the South so that skews things making them appear to have a bigger lead amongst whites than they do.  In 2008 McCain won white women by 7 points yet if only they could vote he would have still lost the electoral college.