I've read through all 10 pages and since I didn't see (not here or I just missed it) it, here is a restatement of what the Democratic party does and why. First, the leadership and most of the party doesn't give a shit about racism. Considering their history, they can't. It is simply a weapon. They don't care about women, or rape. It is a tool, a weapon. For them, the ends always justify the means. They will support a Democrat who fucks babies to death in the street IF he does more "good" for them than harm. If they see their power eroding due to their support, they'll turn on him faster than Ramsey Bolton's dogs (Game of Thrones reference there). So stop wasting your time with useless discussion and argument about whether blackface was racist "then" vs. racist "now". Whether that's him in the photo or not. Truth is not important in the outcome because this isn't about truth, racism, or anything about politics. They are concerned about votes and whether this will be a problem for them in the 2020 elections. For them, keeping or losing the Virginia Governor is a secondary issue. A Democrat Lt. Governor replaces him. If the Lt. Governor has to resign because of his own issues, both offices will be filled by other Democrats. Their priority is whether keeping him in office now costs them votes in the national election in 2020, whether people have long enough memories, whether the Republicans have enough guts to use it for campaigning, etc.
We allied with Josef Stalin in WWII because we needed that alliance against Germany. Most of the Democratic party has no moral convictions and they will support other Democrats who committed acts that they would have said justified the death penalty if the perpetrator was a Republican. So the leadership isn't concerned about the majority of their party, only the less Socialist fringe and the independent center.
Ok, time to get off the soap box. When you try to predict what they will do, look at what the perceptions are and what benefits or harms the party. The political version of "follow the money."