If he is an American citizen, does the 'First Amendment' not protect his right to free speech? Is it
illegal to talk bravado on the internet?
Sigh, freedom of speech is not freedom from criticism.
As for the thread title, its a good bet where America is concerned, the claimants themselves would be the wild card.
So far there doesn't seem to be any wide spread support for war though, but they are definitely arming up.
I think US has recognized that we can't stop the island building short of instigating war, so we are moving on to play up the threat to the other claimants, and using the legal institutions to minimize their effect when it comes to legal passage.
The artificial islands themselves won't effect US operations to any real degree, they aren't survivable in a real war, but against the smaller claimants they are pretty effective.
Basically that means against the US they are a psyops weapon, but potentially a double-edged one.
If the US is not deterred and the credibility of US access to the SCS is not brought into question, their effect on the US is minimized.
The carrier group in the area likely serves this purpose, and maybe as a secondary warning to NK.
Their effect on claimant countries could go either way depending in part on how the US presence is perceived (and of course how China uses them). If the US shows that its patrols won't stop and that its access will not be hindered by those islands, then the claimants might be further incentivized to form coalitions with the US and other balancers (Japan, India) depending on how hard China pushes the utility of these islands.
They will arm up regardless of how the US is perceived and how China uses the islands, that cat is out of the bag for the medium term.
IF the US cannot maintain its credibility then those countries might look to other outside balancing powers who are percieved as more 'willing', or try to warm relations with China in a manner that will eventually leave China's claims undisputed, but will give those countries medium term benefits.
Probably there would be some brief and 1 sided skirmishes (assuming no balancer).