Obviously the destruction of the Buddhas of Bamiyan was an atrocity, it may have been aimed at a particular group, Buddhists, but it is hard to see how their destruction was crime against humanity because of this. It may have come as a grave harm and insult to Buddhists around the world, however none can be said to have been physically harmed in any meaningful way that would constitute a crime against humanity. The oppression during the Chinese Cultural Revolution may be a better example for the proposition, however even in this case it is hard to compare the crime of destroying old Chinese art and monuments, to the mass killing and imprisonment of Chinese civilians during the same period!