There are always a few bad ones. However, IF the other people in the hotel had been ARMED, THEY could perhaps have prevented a few of the deaths. Police cannot (IMHO) protect us from evil people. Often they arrive after the fact (not their fault). Citizens SHOULD carry and help take care of themselves. I've had enough of us being sitting ducks. Obviously people who have serious mental illness or are criminals are not going to think too much about breaking laws. Sheesh.
There is no legal carry in Wisconsin. (Open carry is legal, but not possible.)
I think your right, once this guy pulled a gun and took even just one shot, he would have been put down pronto if folks were armed. Maybe too, some of these criminals would think twice before pulling a gun if they knew what was waiting for them.
Anyway, this stuff is becoming all to frequent, innocent people are not safe in court rooms, schools, church, day care centers, the work place, etc. from criminals with guns, yet the bleeding hearts try to prevent us from protecting ourselves but 'their society' doesn't protect us as much as the criminal. Screw that.