With the caveat that at the tech level required to launch such an attack, destruction of one's home planet would constitute something closer to vandalism of a h

With the caveat that at the tech level required to launch such an attack, destruction of one's home planet would constitute something closer to vandalism of a historic site than destruction of one's species. Of course, if you're thinking of a scenario where aliens at that tech level launch such an attack against us 21st-century humans, yes, we'd be toast.