First, I would never condone such a threat made by anyone, no matter what kind of stress or frustration one is going through. IF ANYONE MAKES SUCH A VILE AND DANGEROUS THREAT, THEY ARE AUTOMATICALLY OUT OF THE QUESTION OF BEING SENSIBLE AND LAW ABIDING.
Second, if you are a law abiding gun owner, you should have had some common sense. Storing that number of firearms and ammunition is perfectly normal, but make sure you have legal and social representation to BACK IT UP. Join the NRA or something so in that case, you will have legal power behind you in case someone f*cks with you over your collections.
Third, it is people like that kid that makes us look bad. Now, what are the people going to think of us? Maniacs, murder freaks? Threat-mongers?