Allies wouldn't refer to them as being detained or arrested like Iran is doing.
No, no, no. The good ol' Iranian boys were just out fishin' and drinkin' when they saw our bad old sailors in distress, so they picked them up and hauled the boats in. Only reason they won't let them go immediately is because they want to give them a proper crawfish boil and anyway they need to wait for spare parts from Samir's Bait and Tackle Shop.
That's all it is. It's not like we have a thousand ships and a hundred helicopters that could come take care of things. Iran just wants those guys to stay away, since they don't have enough crawfish for all of them. That's all. Just folks.