Free trade with China has undoubtedly destroyed US manufacturing jobs, and therefore significantly affected the working and lower middle class, which makes (or made) up most of the people. 
China has always implemented protectionist policies. The US government committed the same mistake of the Brits many years ago, by assuming free trade meant a level playing field and everyone would stick to the rules. In reality, you just end up giving away economic power to those nations who will happily subsidise their exports whilst penalising imports.