The Seals did the job they were commanded to do. It was not up to them to do the confirmation as to the identity of the person they were sent to kill.
They followed orders. Why do people think they would not?
They are not liars, the people that sent them may very well be.
Bin Ladens son looks just like him. Maybe it was mistaken identity. We know he's dead. I guess we'll never know who died that day.