You present it as if the poor country that allows foreign companies to exploit its cheap labor is somehow the one taking advantage of the rich countries. Just ask yourself: is that a likely way for the world to work? Do you think the rich countries just let themselves get walked over in that way by much weaker, poorer countries?
Point-by-point:
> We've had decades of letting China walk all over us.
It's hard to square your view with the fact that American companies have made massive sums of money by exploiting cheap Chinese labor, or with the fact that when you walk around any Chinese city, you see American brands everywhere (Apple, Starbucks, KfC, GM, Tesla, all the fashion brands whose names I don't know).
> They tariff our goods, we buy theirs up.
China has massively reduced tariffs since the early 1990s. Average Chinese tariffs are now around 3.4%, which is similar to tariff rates the US imposed in the mid-1990s.[1]
> They steal our IP, we respect theirs.
Your view of IP enforcement in China is behind the times. Back when China was a largely peasant society shut off from the outside world, it had virtually no IP law. That has changed quite dramatically in the last decades. China is the world's most active venue for IP litigation now. Specialist IP courts have been set up in major cities over the past several years, and the statistics show that foreign companies are quite successful in enforcing their IP.[2]
American companies also take in billions of dollars in revenue by licensing patents to Chinese companies.
> They manipulate their currency, we let ours float.
Many countries intervene in the foreign exchange markets. China does so too, and limits capital flows in and out of the country. I'm not enough of an expert to know whether or not this is a wise economic policy, but I suspect they have good reasons (e.g., financial stability) for doing so.
However, there's no doubt that the RMB floats to a far greater extent than it used to. You can see this pretty easily if you look at a CNY/USD chart showing the past 20 years. The RMB moved very smoothly until about 2012, and since then has fluctuated much more like a normal currency. Of course, like most central banks, the PBOC will pull the breaks when it feels that it's important.
1. https://data.worldbank.org/indicator/TM.TAX.MRCH.WM.AR.ZS?lo...
2. https://www.ipwatchdog.com/2018/05/07/rapid-changes-chinese-...