That's a strange kind of doublespeak. A forklift is "just a tool", a knife is "just a tool", even a hunting rifle is "just a tool". A nuclear bomb is a weapon of mass destruction, designed to kill as many people as quickly as possible. I don't know about you, but I think that's bad. You might argue that it's a necessary evil to stockpile nuclear weapons and maintain the plausible threat that you're going to use them. I can't really argue against that. But calling them "just a tool" is in my opinion trivializing mass murder.