Think about your own question.
1. A man intent on killing many will not stop because of a ban on guns, instead will plan on how to get his guns inside.
2. Had there been one or two other guns in there he might have been stopped before he did the damage he did. Again, that would have nothing to do with posted signs of "no guns"
Guns in the wrong hands were responsible for the killings
Do not leave yourself defenseless by allowing only your enemy to have access to weapons that will damage or hurt you, even kill you.
Nobody expected danger in a moviehouse watching batman.
Is this man therefore a terrorist?
Why has no one even given us a clue about what is this all about?
Was he a hater of batman? movies?