I don’t know how many “White Americans” are Evangelical Christians, but those folks seem to fit your analysis very well. But as far as the rest of your generalizations, I’d say they leave a lot to be desired. A lot of other things have changed since Nixon’s era, particularly the role of unions in the work place. I remember reading that autoworkers made something like $45 bucks an hour in the 1970s, which would have been a fortune (minimum wage at the time was $1.65 an hour). Most of them lacked anything beyond a high school education. Since then, our tax laws have been finagled from a “protectionist” model to a globalization model so that companies could increase their profits by send our relatively high-paying-jobs-for-those-who-lack-an-education overseas while still retaining easy access to our markets, so the GOP had to come up with a boogeyman to explain the declining economic levels of working Americans (not that the DNC didn’t help with changing laws–most of our politicians have been bought by the corporate elites), hence the “evilizing” of our immigrant populations. As our changing economy made it harder for those lacking an education to get well-paying jobs, the GOP resorted to their dog whistle calls to racism so that they could still count on the votes of those they left behind.
So no, I don’t buy into your “most White Americans have no decency” argument. I think your analysis is far too broad-stroked to serve much useful purpose. There are many, many other factors at play here.