We give a shit about the environment.
We don't, and part of why I label myself a liberal-tarian is because I think we should care more. HOWEVER, even if we did, and we don't, it is a more complicated issue than just saying other nations shouldn't pollute. The biggest stumbling block to achieving an international accord on environmental regulations is the strife between developing & third-world nations and modern nations.
We see Developing & Third-World nations polluting recklessly. Consider what they see. They see a bunch of very modern nations who polluted recklessly to get there. We ask them to cut back on pollution. Third-World nations politely say to fuck off because we are massive hypocrits.
The biggest key in getting their cooperation will be ensuring that First-World nations continue to bring jobs overseas in spite of international environmental regulations. In the meantime, it is one of their most effective tools for winning business and improving their economy and well being.
We have minimum wage laws.
"Slave labor" & "Sweatshops" and all this hippy nonsense has no negative basis in economics. It is natural and in fact necessary for nations who are less productive per capita to be paid less money. By moving jobs to these countries we increase their productivity per capita. In almost every scenario these workers make significantly more money than their fellow citizens. So long as the local government is not colluding with international corporations specifically to keep people down (See much of the Middle East & the Oil Industry) people will rise up in response to this (Japan, China, Germany, South Korea & Brazil all immediately come to mind). Hell, even in the case of the Middle East our government regularly pitches in to help keep those oppressive regimes in place so that they can continue colluding with corporations and ensuring that we have secure access to oil.
We have Child Labor Laws.
So does almost every nation in the world. It does still happen, however there are huge misconceptions regarding this. The VAST MAJORITY of Child Labor involves children working in rural areas, usually agricultural sector. In other terms, if the child doesn't work people in his country go hungry! Also, the VAST MAJORITY of Child Labourers work for their parents.
That isn't to say that there shouldn't be laws against Child Labor. The UN has listed Child Labor as a violation of human rights however, so it would be within the United States rights to consider this NOT free trade and prohibit trade with or even charge a US corporation with a crime if they engaged in or traded with Child Labourers.
Child Labor is not a large enough problem to justify making International Trade a villain. It is a Red Herring in the discussion.
Safety & Hazards Laws.
Similar argument as with the environmental stuff. We are the worlds best economy because of the Industrial Revolution, where all four of these things were neglected. Every other nation in the world would gladly suffer an Industrial Revolution if it meant being where we are in 30-40 years. However, we go and act like we know better than they do, and offer nothing to help. Then people like you specifically want to not help them by putting up barriers and regulations to prevent American companies from offering employment overseas. It is LITERALLY the most backwards, First-World-Centric (See: Selfish), Privleged load of bullshit that the populist economic movement spouts and the sad part is that while most of you lot do not know better, the basic economics behind it are and should be common knowledge for every single politician who spouts it.