I think that Oliver misses what happens when someone dumps a commodity. Someone has to want it to get it in trade, or one is stuck holding it.
If China starts dumping dollars, the market will notice and a number of other events will take place, the first being a predictable lowering of dollar's relative value. This makes each successive dollar dumped as being able to get less stock or oil or euros or gold or coffee or tin ore, as it puts the seller in a position of relative advantage: since he sees China dumping, he tries to get more dollars as a hedge against devaluation.
Another effect, depending on the level of "valuation" drop, is that US foreign trade balance changes. Foreign goods become marginally or greatly more expensive. American products/grain/beer/cigarettes become cheaper. US foreign trade surplus rather than deficit.
On the other hand, domestically more dollars stay home. General purchasing of domestic goods look to increase, but there's a hidden problem of inflation or deflation, suddenly, which has the follow on effect of loss of consumer confidence and a recession, or worse, setting in.
And more.
Oliver is looking at single cause and effect chains, where it's a whole lot more complex than that. If China dumps about 1/3 of its dollars and the value drops, the 2/3 China has left start to feel pretty worthless, given their having caused a drop in relative value.
DR
