First off, no serious female debater should ever use the term “manplaining”. It’s intellectually bereft of reason; it’s the 2016–7 version of some Mad Men -era scene where the offended woman stands up, stomping your foot, saying “Well, I NEVER!!!!” and stalks out of the room.
Secondly, you ought to have a look at actual polling on the racial attitudes held partisans rather than tossing out unsubstantiated myth.
Republicans probably do hold more racist attitudes that Democrats do; that’s not news, in that a component of racism is aversion to change. So, racists would naturally gravitate to a conservative party, whether the conservative party holds any racist elements or not. Under the same reasoning, I expect that the few, actual, hard-core, Soviet-style communists in the US vote reliably Democrat. Simple logic.
What is surprising about actual polling, however, is that the difference in racial attitudes between Republicans and Democrats is NOT SUBSTANTIAL. The attitudes held by the Republicans is far less than the “about half” mythology you parrot above, and the Democrats, in many measures, are quite close to them.
A serious, data-based observer can only conclude that racism was not a tangible factor in the 2016 election. For example, on the one question asked in the General Social Survey which is unambiguously racist:
….not much difference. Other questions in the GSS show larger deltas, and the GOP does always come out on top. But the deltas are far smaller than most would assume, and when more ambiguous questions are asked, there’s always the possibility that the answer isn’t picking up a racist component, but another factor.
Hope that helps.