All straits other than the Bosporus (which has some additional rights to Turkey given the proximity to a major city) are international waters for the purposes of free transit, under the Montreux Convention.
It is ridiculous that countries like Australia (a party to a convention) have a say in whether Turkey should or should not pass ships through the strait. This looks like a legacy of colonization era. This convention should be repelled, and the new agreement should be made by Russia and Turkey and other Black sea countries ignoring the interests of colonizers.
The US is is not blocking the Strait of Hormuz. There don't appear to be any US warships even in the Strait at the moment. What the US is doing is enforcing a partial blockade against Iran, largely in waters southeast of the Strait. We can argue about whether this is a good policy but let's not make things up.