So the Filipinos got bullied by the US to park a ship in China's waters and then pretend it's stuck and has to be resupplied and the US wants to escalate it by offering to resupply it in case China doesn't like to get bullied by this fake operation.
The 'dash line' is more or less China's idea of protecting the shipping routes agains the warmonger mad brute (USA), disregarding the fact the it was controlled by China for thousands of years, and disregarding the fact, that China's policy is money and they would achieve their goals by making everybody rich, without forcing homosexuality on the Asian countries.
In all cases, even if one believes these random reefs are disputed territories, why has the US to interfere there? What is the purpose? Stirring up another war, after losing so badly in the Ukraine.