Racists don't need shaming into silence. They need to understand what's wrong with their beliefs.

Going back to the original quote, you need to see that it's not calling all voters a particular thing. There's a simple Venn diagram, one circle of racists inside a larger circle of a particular block of voters.

Educating people out of racism, and removing racism from your society, will change votes as racism is only one aspect of a person's beliefs.