it's just an error in understanding the demographics.
biden's team doesn't seem to realize how badly it did in the first two states amongst the most important voters, or what that means about how appealing he's going to be to them in the upcoming contests.
they bizarrely seem to think that the opinions of illiterate south carolina voters who were told what to do by their congressman is going to overturn the empirical analysis of educated northerners, who are the key swing demographic. it's delusional. but, it's why this party loses over and over again - it's swallowed some kind of kool-aid about race and can't interpret anything rationally any more.
as badly as sanders has fucked up, everybody else fucked up more, in the end. and, he's going to stumble in and save them from their own stupidity....