Yes, I did cite Peterson Institute's study. Peterson is hardly the only source I cited; moreover, the sources I cited are hardly the only ones that present and analyze (while fully disclosing their methodology) the objective/empirical measures of the impacts of NAFTA specifically or free trade in general and that also attest to the net gains from free trade/NAFTA outstripping the net losses.
Who benefits most and/or who benefits least really doesn't matter so long as most people and the nation as a whole realizes a net benefit rather than a net loss. Why? Because the matter is macroeconomic not personal; it's policy made on a large scale with the aim of benefitting the nation on a similar scale.
It doesn't bother me that folks criticize a given macroeconomic policy. All such policies have "winners and losers," and we can all be sure the "losers" will always gripe about having lost in the exchange. What I find totally unacceptable is that the gripers do so without perspective and without giving credence to all aspects of the matter.
- Not acceptable to me: "I disapprove of free trade because I lost my job because of NAFTA."
- Acceptable to me: "I disapprove of free trade because I lost my job because of NAFTA. Even though the nation and people on the whole are better off due to NAFTA, I still prefer free trade. Yes, I know restricted trade will cause price increases and trade wars, but I still prefer it to free trade."
After all, the consideration of any national level policy is not about any one or few thousand people, it's about what's best for the overwhelming majority of people. The first bullet's expression ignores that underlying theme; the second one does not. That is why I can at least respect the speaker of the second bullet's thoughts; that person has made it clear they know the full scope of their preference. They aren't not pretending or intimating that what's good for them is good for most other folks. That's honest. There's integrity in it.