I'm ready for Armageddon... are you?
Responding to a "cyber attack" with a physical attack is so ridiculously out of proportion, it's absurd. If the military can't figure out a way to protect their computers from "attackers", then perhaps they never should have allowed the public onto their network in the first place, you think?
The biggest problem with responding physically to a "cyber attack" is that you don't know who the real source is. In physical combat, you can physically determine who is assaulting you, so you know, beyond any doubt, who to retaliate against. On the Internet, you have literally no idea who the source of an attack is. Sure, you can make an educated guess based on their IP address. But the prevalence of botnets is proof that the direct source may not be the real source. Physically attacking the location registered to an IP address may do nothing more than eliminate an unaware middleman.
Also, it's not hard to imagine how the rest of the world would react to a seemingly unprovoked against by the US, though I suspect the US would be more subtle than sending in a bomber (though I certainly wouldn't rule that out, either).
Just imagine... People growing up during the Cold War thought THAT was scary (and I have no doubt that it was). But if you ask me, the current (and no doubt, future) state is much more scary. At least during the Cold War, you had a good idea of who the "enemy" was.