There are responsibilities that come with owning a gun. It is not a toy.
If you really care about children, you will first protest against the government providing ****ty education to children, dumbing them down, and then you will worry about gun rights of adults. The tragedy is that although kids got killed by bullets, a lot of the children that live grow up to be adults who are dead inside. That is where the real tragedy is. And it is even more tragic because you can't measure it in statistics. Only in real life experience.
Also, as I said, criminals don't care about the law. Making guns illegal won't stop people who don't care about the law from getting weapons. And psychopaths are even harder to stop because they don't care about consequences either.