No it doesn't. The US does whatever is in its strategic interest, and ignores everything else. Always has.

And China is following the law... from their perspective, all their actions are in compliance with the law. We just disagree about their perspective.

If you take China's claims about the South Sea Islands at face value (you shouldn't because they're bogus, but let's pretend here) then their actions are in compliance with the UN convention. Nobody else agrees with their South Sea Claims, so from everyone else's perspective, they are breaking that law.

Instead of just bickering over if they are breaking the law, which will achieve nothing as both sides are utterly convinced of their correctness, instead we should focus on getting China to withdraw their claims. Just telling them their claims are bunk isn't going to work, especially given how much Chinese culture demands maintaining face and admitting wrongness is not allowed.

We've tried the bully approach for 70 years. It doesn't work.