So you are saying we were irresponsible to have used them when we did? However, WMD extends to more than just nuclear weapons, so your statement doesn’t pass as valid.
True; if one follows the news, there have been stories of ISIS having WMDs these past few days and the stories are not talking about even dirty bombs, they are talking about chemical weapons.
Yes. There is no legal, ethical or moral principle that would ever allow for the indiscriminate targeting of civilians in a military campaign.