Once again no matter what the restrictions the US announce, it won't stop the Chinese government getting hold of whatever AI accelerators they want through the grey/black market. So this is just another way of claiming they are stopping them being used for military use but its more about trying to stop Chinese companies catching up or getting ahead in AI.
After all the US can't stop the tonnes of illegal drug and weapons flowing across its border every year what makes them think they can stop high end GPUs getting smuggled out?