When we were keeping the Straits open, we were doing it in our own best interests but also on behalf of the Free World to ensure the economies of all countries (mostly us) maintain access to the petroleum shipping on those waters.
The Russians and the Chinese are doing it to ally themselves with a repressive, violent regime and are doing it as a political move. It is a stunt in any case.
We no longer need to keep the Straits open. We are now energy independent of the ME. We WERE doing it on behalf of the EU essentially.
We no longer have to give a toss as to whether the straits stay open.
However, attack one of our embassies, and just over a half a day later you can expect us to shove an expensive firecracker up your keester.