Helping the locals sort out a natural calamity like this is hardly "cleaning the streets" sharpend, particularly when other agencies not to mention locals and private contractors, many unpaid, are at full stretch. I don't follow that whether soldiers are "keen to fight in Afganistan" or not has anything to do with it (that ones over, you may have noticed). They're being paid by the government(unlike many others helping) and most are keen to be doing something with a visible and tangible public benefit.