Advocates' central contention was that the deal would eventually lead to a political liberalization of China -- which it hasn't -- and would enable the United States to so increase exports to China that our Chinese trade imbalance would end -- precisely the opposite of the effect that normalizing trade relations has actually had.
Economists often distinguish between the short term effects of policy change versus the long term. Yes, free trade does create some short term pain, but the long term effects are positive. We are now ten years later and things have only gotten worse for the U.S.
How long is "long term?" I'm reminded of the comment by the legendary economist John Maynard Keynes, "In the long term, we'll all be dead."