Sure, that's perfectly logical; we could also wipe out all the weaker nations like Africa to make sure they never become a problem, too. We could also wipe out, say, all the small countries before they develop a significant military. There are some that have no significant military in any way, shape, or form; logically, we should bomb the crap out of them or invade them. Just to make sure, you understand.
For your perusal, I propose we wipe out these countries
that have no armed forces.
I guess I just don't see the logic -- and don't see how any species at all could arrive at this as a logical conclusion -- in going out of our way (or for any alien species to go out of their way) to attack another planet.