There are winners and losers. I don't mean to be callous towards the losers, but the baseball analogy stands. Integration of the negro league with the white league cost a lot of white and black baseball players their jobs in the short run, and most of the anger at the integration was from players that couldn't compete.
And sorry but what are you talking about with NAFTA? With the exception of the drug economy (which is by no means free and transparent trade), Mexico has made tremendous progress since 1993. Where is "plenty of evidence" that the same growth would have been achieved by trade restriction? People who oppose trade spend a lot of time emphasizing incremental losses, in the way you could show lost income from baseball pitchers who lost their place on the bench to Bob Gibsons.
All these arguments were made in Massachusetts when the Worcester textile industry relocated to North and South Carolina, it was all "doom and gloom" and externalized pollution. It was disruptive but Massachusetts economy did better by getting out of textiles and North Carolina did better by getting into them. Now NC has lost it's textile industry, and has Research Triangle in its place. A rising tide lifts all boats not anchored by protectionism.