If people were always rational and clear headed, there would be no problems with gun ownership. But that is not the case.
And it is when the line has been crossed, you cannot tell until it is to late.
Or, in your case, cannot do anything against it until it is to late. (i.e. legal guns but did nothing wrong so that they could be taken away)
The problems with guns: they are massive enablers.
Yes, you could kill people with other items as well, but guns make it SO much easier.
Some other notes:
Comparing to other deaths like accidents or whatnot are simply stupid straw men. Water kills more people, should we ban it?
And other people wearing guns to 'protect themselves' is not only a mute case because the negative occurrences far outweigh the positive ones, but also those are the kind of people that should not wear them (a little paranoid, are we?). Not to mention if they even use it. That governor was surrounded by body guards yet was still shot.
How often have guns been used for good?
Lincoln, MLK, Malcom X, Kennedy, that governor.
Finally I will say this:
If you, regardless of the evidence that the solutions to your problems are visible, continue to ignore them, you get what you deserve.
So if you do not want to change anything, then don't. But don't come crying when another crazy shoots up a school.