Legally I agree there is a difference. Morally, IMO, there is not. The aid you give may differ based on your ability or training, but the moral obligation to render the best aid you are able, to do SOMETHING even if it is only hold the hand of the injured and give comfort, is still there.
There is a difference, for most people, between being a civilian and being a professional soldier or law enforcement officer or EMT. A civilian gets to pick their battles. If the situation is unclear or the odds are too bad, now that I'm a civilian, I can walk away. The professionals and especially the military professionals don't have it so easy. God bless them.