Just how is he a hero?

[deleted]

The word 'Hero' is so overused in American culture that the word is meaningless now.

I disagree with your points entirely.
Whether he was or was not facing the same danger as the other passengers on the plane is irrelevant. In any event, heroes are to be found facing the same challenging or dangerous circumstances as those they save. In Sully's case he took the necessary precautions to avoid the dangerous fate that awaited him and his passengers if he hadn't.
Sully's entire conduct throughout the ordeal to land the damaged plane reflects in my opinion his willingness to risk and sacrifice whatever was necessary at the time to save the 155 souls, including his own life and reputation.
And he didn't act out of self-interest at all since his motivation was to save all the lives onboard his plane.
Further, by definition a "hero" can be one who is "noted for special achievement in a particular field" and Sully's landing the plane on water without any loss of life was and still remains a miraculous achievement!

I'll tell you who reflects those points you noted, however. The co-pilot of Germanwings Flight 9525, Andreas Lubitz, that's who! He acted entirely out of self-interest! He took no risk whatsoever and made zero sacrifices to help or save anyone onboard that doomed flight! He was actually the person responsible for placing everyone onboard that plane in danger and by his selfish actions slaughtered them! He is definitely not a hero by any measure.

he kept a cool head under immense pressure

maybe that doesn't make him a hero but he is cool in my book

"Abortion is green!"
Doug Stanhope