Bernie is basically textbook chauvinism. He explicitly cares more about people similar to himself than others, starting with nationality. His complaint of, say, "sending jobs overseas" is that it decreased moderately well-paying union jobs for (predominately white) US citizens. He doesn't care that the workers overseas are even more exploited. He only uses elements of their exploitation to villainize the countries those workers live in.
This is why global empathy and appreciation of proletarian struggle is so important. If a person walls themself off from this like Bernie, they end up becoming the oppressor.