Fascism always wears populisms clothing, but they aren't therefore directly equivalent. Bernie and Trump both support tariffs but for different reasons (and to different degrees). Likewise you can gush about 1950's factory workers for different reasons. One is purely to do with economic power of the lower class, the other is to do with supposed Golden age of American history. They have overlapping bases but that's merely a part of their Venn diagrams.

Also Trump already passed the massive tax cuts based off the assumption of income from Tariff's, and those tax cuts disproportionately benefit the rich. I don't think we really need a conspiracy to explain the likely motivations.