To give a fair and balanced response, yes, it's effing ridiculous - however, the fact that this is to prevent what could possibly be (based on past experiences?) a day which could see some degree of violence and maybe even bloodshed... it's not such a terrible idea. Of course, for us, the teachers, we have to teach which annoys us, but in principle it's better than the authorities thinking something big could occur and not doing anything about it. Put it this way, if you were Japanese, in China, you'd certainly appreciate it (even though the war was a looooooong time ago now)!
Still, it is all very f*cked up and yeah, I would teach (Pearl Harbor, 2006 version?) so long as i got two days off the week after. Oh, and I would also voice my unhappiness at the late notice (lack of timely communications - AGAIN)!
More than likely, the school has been told to do it by the local authorities.