This insistence the Trump's America First is like the America First Committee of 1939 is crap. Crap that is perpetuate by Leftist media propaganda hit pieces. The 2017 America First has nothing in common with the 1939 America First Committee.
The 1939 America First Committee was a movement that wanted American isolationism to keep America out of the European Conflict.
America First Committee - Wikipedia
To define the 2017 America First, I will use Donald Trump's own words:
“Americans must know that we are putting the American people first again,” he said. “On trade, on immigration, on foreign policy — the jobs, incomes and security of the American worker will always be my first priority.”
“I will view the world through the clear lens of American interests,” he said.
“We will no longer,” he said, “surrender this country, or its people, to the false song of globalism.”
Trump's America First Policy Is Conservative Policy
Nowhere has President Trump stated that America should be isolated from the rest of the world.
If he's going to renig on trade deals and tariff Mexican imports he's kind of an isolationist just like England isn't going to get the benefits of being in the Euro.
The opposite of isolation is not being the world's bitch.