As an outsider (Canadian), I find it weird how some Americans have such a strong sense of patriotism connected to their currency. Don't get me wrong, the US is a great country and I love visiting, and Americans are justified in being patriotic in general. It's just odd to conflate love for one's country with love for the paper used to exchange for goods and services.

As for Trump, I doubt he actually truly cares that much; he happily owns assets in other countries (eg golf course in Scotland). In my mind he's largely paying lip service to the dollar to score cheap political points.