There is no proof by you have to suspect that the White House put a target on the backs of Seal Team Six when they went out of their way to show off what they did to Obama. If the Defense Department hadn't stepped in old Biden was going to announce their family names.
Now a number of them are killed in Afghanistan. It wouldn't take much more than a scrap of paper or a whispered name for the insurgents to know that members of Seal Team Six would be on that helicopter. This is the first helicopter taken down with a rocket. Those have to be in short supply for this one use.