Sure but you asked if they are subsidizing them, the answer is no. Is it cheaper than waiting to load empty containers? It could be depending on the incentives, even if those short-term incentives are damaging to long term prospects you would be surprised how short-term most businesses think. Biggest influencing factor I can think of right now is that many importers/exporters are willing to pay exorbitant fees to get product from China to the US. This is specifically acute in areas/industries that there are no other viable source, say for instance LiFePO4 batteries. These are absolutely key to a huge number of things happening in the world right now and are outside of a few very isolated plants (CATL has one in California) made entirely in China.

There are so many insane distortions happening because of supply crunch that subsidies and trade nonsense are actually starting to become irrelevant. (though I really do hope USA sorts their shit out, their China policy is fucking up the world for zero reason).