I don't get it either. Free Trade has improved the lives of billions of people. It helps prevent wars and binds people and countries together. I just don't get the Hacker News Hate on Free Trade.
That is not free trade.
When it comes to TPP in particular, I am radically opposed to their proposed IP laws. EFF has a short write up on how TPP undermines with digital IP: https://www.eff.org/issues/tpp
Most importantly, it's not a "free trade deal". It's just a "trade deal". Australia's trade deals in the past with the US have done things like removed tariffs for all US goods coming here, but not removed tariffs the other way around. We're definitely the little brother in this relationship.