Of course, adding to the stupidity here: Let us imagine, generously, that the shipwrecked survivors were actually signalling for help from another cartel boat. If the forces involved actually honestly believed that, and actually honestly were trying to destroy the cartel, it seems abundantly obvious to anyone with two brain cells to rub together that the survivors should have been allowed to continue signalling, since we know for sure that the wrecked boat was already close enough for visual contact, and soon would be right smack dab in the range of the missiles were known to work in. So obviously if another cartel boat showed up there, the US forces could have blown it up too. That they did not lure that other boat in so they could do what they had proven was possible to do, seems as so often is the case in conservative arguments these days, to result in two possibilities. Either they are lying or they're too stupid to do their job properly.
Instead, they massacred the survivors, insuring of course that no evidence or testimony would be possible, but also insuring that if there had been another cartel boat in the vicinity it would have left unharmed.