No serious constitutional scholars interpret that introductory clause as restricting the right to bear arms to militias. That interpretation is as illiterate as saying the First Amendment requires disrespect toward religion, since Congress can't make laws respecting (i.e. "regarding") it.
As for the rest of your "argument", abusus non tollit usum. And your inappropriate generalization from one incident of gun violence could also be used to outlaw parenting, since some people abuse their children.
Finally, since you seem to think "nutter" is a word, you're either not an American, or you're a poser who affects a foreign dialect (that's British English). So who cares what you think about American politics?