He didn’t say they shouldn’t get to vote. He said the result is irrelevant because these particular voters don’t matter to who wins the general election. Not all black people are the same. South Carolina’s voters getting to have inordinate influence doesn’t mean we’re selecting the candidate black voters in general want, and since they’re not even close to being competitive the extra focus there is a waste. If we wanted to elevate a diverse state (good idea), either of their neighbors (especially Georgia) would have been a better choice.