The reason we might have large, group, trade deals with "a wall street christmas list of horseshit" is because tariff's are actually relatively low in many places, and in any case, tariff's are far from the only, or even biggest, thing that might be a roadblock to trade.
Really, these deals are much more about stuff like countries unifying regulations (maybe having 1 set of automotive regulations to comply with instead of a whole bunch, for example), strengthening intellectual property in countries where it is weak, and (ideally) setting minimum standards across a large, and thus influential, block of countries to curb a race to the bottom (and the TPP would have raised environmental and labour standards in a number of countries).
These sorts of things have been attacked as not actually having anything to do with trade, but they really do. IP stuff specifically gets attacked a lot, but creative industries are a big part of the American economy, and they employ a lot of people. You'd think people wouldn't be so aghast at the idea that IP rights would be considered an important part of trade between countries.
This does leave us negotiating a lot of policy between countries, usually in secret, which is very unpopular. But agreements that merely reduce tariff's wouldn't really achieve much. And I get that maybe some of the provisions might be flawed. But my argument isn't just that free trade is good, but that there are good reasons the TPP would touch on so many topics that many wouldn't think would be part of a trade deal. (The full text of the deal is publicly available, so people can be specific with their concerns if they'd like)
And when people talk about the TPP holding China to higher standard this is what they're talking about. If enough people signed on to the TPP the other countries in the region will be pressured to then also sign on, accepting the unified regulations and minimum standards that might become the rules driving trade in the region.
I think you are highly exaggerating. Your example about automotive regulations is a fake example, for example. There is nothing in the TPP about unifying automotive regulations. Moreover, we have international organizations like the ISO (International Organization for Standardization) that already work on that issue.
The environmental and labor standards in the TPP were a joke--China would have already qualified under the standards set in the TPP. These were put in as a talking point to sell the deal to the left.
It certainly was not a deal that trade unions or environmental groups were advocating to get passed (in contrast, environmental groups have campaigned for the climate treaties):
NRDC:
https://www.nrdc.org/media/2015/151105-0
This trade agreement would allow foreign corporations to challenge our health, safety and environmental protections in a foreign tribunal outside our legal system, and it would weaken those bedrock safeguards in the United States. While there are some positive conservation measures, the agreements substantial shortcomings should lead Congress to reject it.
Sierra Club:
http://www.sierraclub.org/trade/trans-pacific-partnership
Threat to Forests, Wildlife, and Fish. While the TPP environment chapter should set strong and binding rules to address conservation challenges like illegal timber and wildlife trade, its rules will likely be too weak to have an impact on the ground and are unlikely to be enforced, rendering the chapter essentially meaningless.
Unfettered Rights to Corporations. The TPP will include provisions that give corporations the right to sue a government for unlimited cash compensation -- in private and non-transparent tribunals -- over nearly any law or policy that a corporation alleges will reduce its profits. Using similar rules in other free trade agreements, corporations such as Exxon Mobil and Dow Chemical have launched over 600 cases against more than 100 governments. Dozens of cases attack common-sense environmental laws and regulations, such as regulations to protect communities and the environment from harmful chemicals or mining practices. Read more here about how harmful investment rules included in other trade pacts have led to the attack of climate and environmental policies.
Increase in Dirty Fracking. The TPP may allow for significantly increased exports of liquefied natural gas without the careful study or adequate protections necessary to safeguard the American public. This would mean an increase of hydraulic fracturing, or fracking, the dirty and violent process that dislodges gas deposits from shale rock formations. It would also likely cause an increase in natural gas and electricity prices, impacting consumers, manufacturers, workers, and increasing the use of dirty coal power.
Greenpeace:
http://www.greenpeace.org/usa/news/greenpeace-response-to-the-trans-pacific-partnership-text/
The text includes toothless ocean conservation provisions with slippery language that encourages but does not require bans on trade in illegal timber, shark finning, commercial whaling and illegal, unreported and unregulated (IUU) fishing. There are better ways to protect the worlds oceans than whats in the TPP.
The treaty ultimately fails the laugh test: It doesnt reference climate change at all, while enshrining new legal means including investor-state dispute settlement (ISDS) provisions that would give corporate polluters the right to directly challenge state and federal regulations. It would also accelerate the climate crisis by facilitating the build-out of new liquid natural gas (LNG) export terminals. More LNG trade means more fracking for natural gas and more emissions of methane, a greenhouse gas 85 times more powerful than CO2. By introducing this treaty on the cusp of the Paris climate summit, President Obama has contradicted his own stated commitments to do everything in his power to solve the climate crisis.