There's also a Maslow hierarchy argument: millions of people have lost their jobs due to a variety of reasons, from "outsourcing" to "automation" to the "energy revolution". Social arguments, KKK, racism, etc. are meaningless when you worry about putting food on the table. Trump appealed to that sense.
The truth is that most of these jobs aren't coming back. Trump told them what they want to hear, namely that he will fight to bring back the jobs. Clinton told them what they had to hear, namely that many of these jobs aren't coming back and we need to figure out where the displaced workers fit in the working society. Needless to say, voters preferred Trump's messaging.