People are racist because people do simple pattern matching and the people and groups have a bunch of overlap with the people and groups that did the border opening (which was also bad for the people hurt by the off shoring) who have a bunch of overlap with the people who were making the most noise about racism.
It's literally "owning the libs" but on a cultural level.
I'm not saying it's smart or right, but it doesn't take a genius to see what's going on here.