If he were racist, he wouldn’t ask them to “show us how it’s done”. He was simply using rhetoric, a little clumsily perhaps, in calling them out as having no credibility because they have accomplished nothing. So he said “go back and fix your place of origin (which would include places like NY and MI)” and then you will have some experience to teach us things.
A racist doesn’t want to learn from people he hates.
Baby Come Back
https://youtu.be/vDkdjrEqu1I