Opinions about whether or not to arm pilots inside the USA are fairly irrelevant if we are not living there and/or don't fly a N-reg aircraft. It's their country and they can do as they please inside it (just as others get to decide what happens in their countries - that's democracy!).
Unfortunately(?), guns do not make you safe. The US has the largest defense expenditure/forces in the world and could reduce most if not all countries to rubble if they so chose. That didn't stop Sept 11 just in the same way as guns in the cockpit won't stop all terrorist attacks on aircraft. To a certain extent, arms are simply there to make people feel more secure. Dangers and threats still exist and people think that we can get rid of them all. We can't. Life doesn't work like that.
So take guns into the cockpit. But you will find that:
1. This will not stop terrorist acts on aircraft.
2. Accidents happen and therefore, in all probability, someone will be accidently shot (this will be put down "acceptable loses to achieve a given outcome").
3. You can't plan for every eventuality. Life is dangerous (it will kill you in the end
) and that while you may think arming yourself is going to make you safer, this is probably not the case.
On a final note, the US needs to accept the idea that other countries don't want guns in their aircraft's cockpits (even in aircraft going to the US) and that is their choice! If you flying Europe, Asia or Africa let your feelings be known to
your country's aviation authority. Be vocal about what you want. Don't accept guns in the cockpit just because the US does it.