I think a lot of them just had some theories crammed into their heads in college and left thinking they possessed great knowledge and wisdom. Now they seem incapable or unwilling to look at the negative results of those theories as implemented by our government over several decades.
Some are so in love with their theories that they'll never abandon them. And some might be profiting from the international trade scams.
My real position on this is: mostly free trade between nations of comparable living standards. And tariffs on imports from nations with far lower living standards, unless those have some unique product not available elsewhere.
But, then there are all those non-tariff trade barriers used all over the world. We should really be negotiating nation by nation rather then with all this big trading blocks.
I agree with your assessment.