Why are Americans reacting so strangely to the Gifford shooting?

I mean to a rational mind, the main problem is that anyone can buy GUNS, which was the real cause of this murderous scheme. Not everyone should bear arms, it's very foolish I think (at least to someone living in Europe) "The right to bear arms" was laid in the Constitution like 200 years, and it has definitely become outdated, don't you think? In the 21st century! No one, without special training and special aptitude tests should have the right to bear arms. the main problem is that GUN sales bring in a lot of MONEY for many people in the US, that is why many are reluctant to abolish/repeal this right. it's the same in the health care sphere, US is the only first cl nation that doesn't have universal health care, honestly. have you ever even considered how many people are actually saved just because they bear arms? I mean if someone is attacking you nowadays, they obviously think everything through (in case you take out your weapon) I have always been shocked and astounded to find that a high school student in America can just come to school with a gun and shoot people at random. this is very horrible and this trend is a virus (just like terrorism) which should be annihilated. and people who undertake such ventures should be given the death penalty, regardless of whether they're sane or insane. then there would be order. I mean after such an anomaly you Americans actually think people elsewhere will respect you and your so-called "democratic state"?