It's a combination of all three.
Living here in WV as a Republican, I can assure you that Byrd's continued lifeteime reelection has everything to do with being a Democrat in a heavily Democrat state, along with the fact that obtianing seniority in the Senate makes that Senator (and hence the state he "represents") that mich more influential.
Most democrats can't be embarrassed, they have no heart or
soul. We, in WV, are humiliated by Byrd. We are not
racists.
We have very few Blacks in WV - less than ten in my county.
To me, and everyone I know, they are just people like us.