Irony of WMDs

Should only nuclear weapons be regarded as WMDs, what about the pistols, guns, which normal people carry. They are also capable of mass killings; massacre. Well its about the Virginia Tech killings that happened yesterday. And I was horrified to know that any citizen in USA can have a gun for self.
That just makes every single person vulnerable to attack. I slight depression or a small fight can do it all. And that just explains the shoot-outs that has happened in schools. And just anybody can be put to do that, given the fact depression is a widely spread symptom and people in US catch it very easily.
Irony is a nation which believes that other nations should not hold weapons for defense purposes and carries on pre-emptive wars where they only doubt of WMDs presence, allows each citizen to carry weapon for there own safety.
What kind of logic is that? And let me be a little sarcastic and ask, docent the government have faith in its PDs for the safety of the citizens?

Well politics and logic are different breeds altogether.