@Lash,
Somewhat cliche, but if not us, then who?
Again though you keep focusing on this as some sort of humanitarian response or act of policing. It wasn't either.
It was, pure and simple, sending a message to global thugs and our foes.
If you cross one of our lines, you will pay; and if you're not sure what those lines are, be very careful and try and figure them out before you take some outrageous and/or provocative action.
It was an exercise in the wielding and management of power when faced with powerful foes. Whether on a playground, a barroom or the global stage, you need to make your opponents believe you will act when provoked and that they will not like how you act. If you display indecision or weakness you invite aggression. This is primal stuff writ large.
Far to much analysis has accompanied this strike.