You do realize that trade agreements, tariffs, bans, etc. are all bargaining chips in diplomacy & that when it comes to bargaining w/ China, we have to use these tools very delicately, right? Banning trade with China makes about as much sense as shooting your conjoined twin through the heart you both share. One ban in one area on one thing leads to retribution in another area and possibly escalation & so on. Trade barriers almost always lead to higher prices on goods, so there's another side-effect as well.
China has 1.3 billion people and zero care for the environment. That is not going to change anytime soon. They did a decent job cleaning up for the Olympics, but that was only temporary & for show for visiting countries (& to make the air clean enough for athletes).
Our options are limited & our bargaining power to force change in China is limited, so get used to the status quo or come up with a viable alternative. Do you know WHY we choose to buy our goods from China? It's because they have low wages, no benefits, and no environmental policies, so companies can afford to set prices low. It's cheaper to ship raw materials to the other side of the planet to be processed & then shipped BACK than to have them processed here in the US with US labor. I kid you not. We send wheat & flour to China to be processed into noodles & shipped back.
Why choose environmental policy as a stance for trade barriers? Why not human rights or worker conditions or even minimum wages? If you're going to get upset over subsidies, we subsidize food which we export & we and other countries subsidize banks, auto-manufacturers, etc. etc. It's much more blatant than lax environmental laws, too.
Why don't we just ban all trade w/ everyone but democratic 1st world countries with high environmental and working standards? -- Because the cost increase on goods will be astronomical, that's why!
If you're going to be all high minded and idealistic about our trading policies & threaten sanctions on our biggest trading partner and investor, you'd best be ready to back it up & have a backup plan for the consequences...