Just to be clear, liberals who claim their preferred candidates did worse strictly because of racism ARE acknowledging that, in such a scenario, these racists would be Democrats who would normally vote for the party, yes? It's not like Republicans are more likely to vote for a White Democrat over a Black one; they're not voting for the Democrat, period.
There's a third option when you register to vote (Independent).
Okay, so a mix of registered Democrats and independents. It just seems that too often some misguided Democrats use the following logic: My party's non-White nominee did worse than previous White nominees --> he/she lost because of racism --> the "other side" is racist, when in fact it would be a negligible amount of Republicans/conservatives voting on race.