I have to think that this decision to initially exclude the British frigate was undertaken at the level of the 5th US Fleet (Bahrain) or possibly by the Commander, Battle Group. The reasons may have been as simple as that of timing — IOW’s “How long do we have to delay while waiting for the HMS Argyl to form up?”
I love criticizing Obama as much as the next guy, but this probably isn’t related to Obama’s loathing of all things Britsh.
I agree. Also, the Navy may have decided that one more frigate was not worth sacrificing unity-of-command.