The shooting was a terrible and tragic event. And while I know this isn't really in-keeping with the tone/tempo of the article, all I can say is that any society which can lay legitimate claim to being a 'free' one has to permit its citizens sufficient freedom to behave badly--even terribly and tragically.
But there were definitely failure points along the way here which might have been addressed, primarily by the hotel staff. Not saying they *should have been* addressed, just that the *might have been*. Would fostering a culture of greater individual responsibility contribute to those failure points being addressed? Possibly. I honestly don't know if there's a remedy to this type of tragedy that doesn't unacceptably curtail freedoms.
My thoughts are with the victims and their families.