I'm certain our entire nation is outraged about that soldier (and any of our soldiers) being killed, but the fact that we can still act with compassion and fairness rather than vengeance is what makes us such an excellent society. It's the same reason we have laws and sentencing guidelines, and why we let judges set sentences rather than whomever was wronged (or their relatives). Without this you have vigilante-style revenge, and as a nation and as a people we really are better than that.
Revenge? What revenge? The point is plain - kill them, or they will gladly die trying to kill us.
That said, really good revenge is still better than really good sex.