Keep your story straight, flash. First you claim claimant countries that are no peer to China are doing something meaningful now, then you claim that over 10 years ago when the Chinese presence was dredging barges nothing could have been done.
Huh? Those aren't claims but facts, going back to the Battle of the Paracel Islands in 1974 and the Johnson South Reef Skirmish 1988 to the; clashes between China and the Philippines over the Scarborough Shoal, clashes between China and Vietnam over the Spratly's and oil blocs, and clashes between China and Indonesia over fishing rights. Finally there was Philippines v. China at the Permanent Court of Arbitration, which China lost.
Here are the Vietnamese not confronting the Chinese in the SCS.

As to your comment regarding SLOC, I say, for now. If they chose to in the future they now have established military and logistics capability to interfer with far greater ease than before.
That would be a big redline no one has crossed in a very long time, and one that would likely affect them much more adversely in the long term given the vulnerability of their sea lanes. If war breaks out it is a different story
Your Trump frustration is showing. Very much beneath you and not germane to the debate at hand.
A gratuitous shot but since we are talking about action against China I thought it was certainly germane.
The question stands, though. What could have been done? If you think that the US engaging in military operations against China would have been a viable strategy, please make your case.
I keep wondering the same thing.