"Sixth, he's trying to turn this into an us vs them argument. China has benefits a lot from trade with America, since 1981 extreme poverty in China has gone from 84% to 12%. If instead of taking the nationalistic stance that "Free trade is allowing the Chinese to take all our jobs" can't we say that the 72 point decline of extreme poverty in China is a good thing and the benefits of that decline far outweigh the lost jobs in America (assuming there really are lost jobs)."
That is only your subjective position on social welfare, however undisputable you may see your position (preffering the welfare of the many over the welfare of the few). The actual distribution of benefits of free trade is very important in real world. That's why we have politics. It's also the reason this
"But Draug, its not a zero sum exchange. There hasn't been a 72 point increase in poverty in America.
Trade has done more to alleviate poverty then either charity or foreign investment. That alone means that liberals who claim to care about the poor should be massive supporters of free trade."
is irrelevant. Why should only 72% increase in US poverty outweigh the decrease in China? What kind of people have utility function going like "I enjoy being worse off as long as my foreign counterparts are doing better at a stronger pace"? Why should the unemployed shut up because someone else is profiting from having their job? Even if the "someone else" category incorporates more than the other worker - shareholders of the other worker's company, customers etc.? Should American shoemaker gladly accept losing his job so that a Chinese shoemaker, an American Nike shareholder and his neighbor can enjoy a job, more dividends and cheaper price?
And if anything, "trade" with China is far from an example of what usually passes for free trade. Establishing manufacturing plants in China is restricted and regulated, as well as repatriation of profits, which is why a much larger share of benefits of trade than usual actually stay in China instead of moving to US. China is using its power leverage to get more of the mutual trade than small Third World countries can. That's why it's doing so much better than almost every other developing country. It's a victory for regulated free trade that shifts the balance more in favor of the developing country.
Economic theory is quite clear that a small country having a FTA with a big one benefits more than the big one - because it assumes "fair" distribution of the benefits. In real world, things like institutional setting might mean they get a very small share of the mutual benefits - the small country is still better off, but barely. The distribution is not fair but still beneficial. If we then look at the section of population of the smaller country that benefits from the trade, maybe it's only a small subset that benefits. But maybe it benefits a lot. Maybe it benefits much more than other parts of the population that actually not benefit at all, but lose. Does the great benefit of the few outweigh the loss of the many? Should the net gain of the country be the selected measure instead of, say, minimizing the loss for every single individual? That's a political issue. A real world economic issue is always ultimately based on politics, because no one ever benefits at the same pace. Even if the policy pushed everyone towards Pareto-efficiency (where we will never arrive), as long as someone benefits less than others, it's still a political question and the policy might be ultimately rationally dropped.
tl;dr even if Free Trade always creates Greater Good, it might not be desirable.