It's really pretty simple. While it may be a nice policy to respect the history of the fellows who are trying to kill you it is in no way an obligation, moral, financial, legal or otherwise. We spared Kyoto, we bombed Dresden and more to the point, Monte Cassino. The latter was perhaps the best pure example of what I'm talking about - a priceless, ancient artifact of Christianity that was only briefly a German observation post that was flattened utterly because it might have been a defensive position. Too bad, but since it was my future Dad downhill I have kind of a vested interest in having reduced the place to rubble. So do all the other sons and daughters who didn't lose their chance at life so someone could leaf through the undeniably beautiful illuminated manuscripts.
I'm as big an ancient history fan as anyone, having bought some certified fakes along with some genuine articles. I own a couple of cylinder seals that are four thousand years old. If I thought that it would save one person's life I'd stomp them flat. Four thousand years from now if somebody did the same thing to something I made, I'd applaud them. Priorities.