Alabama’s White Voters Abandoned Roy Moore in Large Numbers

I’m curious about something, but first a caveat: data from exit polls isn’t always perfect. However, more reliable data from the ACS and ANES surveys aren’t available yet for the 2017 vote in Alabama. And that’s not all: exit polls aren’t even available for Alabama every year, since everyone knows who’s going to win there and it hardly seems worth it. Still, exit polls are all we have right now, and we do have exit polls from both the 2008 and 2017 Senate races:

There’s not much change except in one category: a whole lot of white voters who voted for Republican Jeff Sessions in 2008 decided to vote for Democrat Doug Jones in 2017.

Obviously Barack Obama was also on the ballot in 2008, and that makes a difference. At the same time, there doesn’t seem to be anything all that special about either black turnout or the huge share of the vote they gave Jones (98 percent vs. 90 percent for Vivian Davis Figures in 2008). The biggest difference appears to be in the large number of white voters who apparently couldn’t bring themselves to vote for Roy Moore and voted instead for the Democrat (30 percent vs. 11 percent for Figures in 2008).

Am I missing something here?