I honestly can't tell what his point was there.
Really? It seems pretty obvious to me. Sanders was suggesting that, since the south is already a "lost cause," Democratic support in that region may be worth less.
Of course, whether or not Sanders is actually stronger/receiving more votes in "competitive" states is not clear, so his point is pretty tenuous, but he's obviously not making a racial statement as the thread poster is implying (even though I'm certain the thread poster knows better, and is just trolling).
EDIT: I see that the thread poster has since changed the title of the thread so that the only reference to racism/the idea that Bernie "hates blacks" (as was in the original title) is a brief line in the original post (which has also been edited).