Still very much (1) a tactical mistake and (2) not everyone of the 60 million people who voted for trump fits your description. Working class people fucked over by the establishment voted for the "anti-establishment" candidate, surprise surprise.
Again, that speech was made early in the campaign. Obviously not talking about 60mil people. But, definitely didn't help, especially once pundits pounced on it.
I'm not saying it wasn't a bad decision, I'm saying it's very understandable why people did what they did. Calling them stupid rednecks is very easy and makes you feel better than them but it's lazy and untrue.