This is ridiculous.
Aside from the reference not actually calling it a war crime, saying that "some" characterize it as one doesn't make it one.
War crimes are serious violations of the laws of war.  The key words here are "laws" and "war."  Unless one lives in a corrupt town, laws are made by legislatures, or in this case ratified by them, after being written and argued over by diplomats in consultation with their military's generals.  The laws of war were written with the understanding that killing large numbers of people may be a legitimate and necessary part of that process.  The laws of war were not written by corrupt and ignorant peaceniks sitting around dreaming up what they think would be moral.
I'm deleting this section.  It's not salvageable.