It's not really debatable that people are less racist now than they were then and that this goes for supporters of both parties. Ironically, the issue itself suggests this - the Central Park Five ad was pretty standard race-baiting at its time and would be more controversial today.
What is different is largely salience. We live in a culture war era where people prioritize these sorts of issues and strongly identify politically with them. It's not as if say WV voters are more racist now than in the 90s (they're probably less racist if anything) but they vote based on their views about this. There is also less media gatekeeping, so we get to see more unfiltered folk opinion than we used to and that is always a little terrifying.
