It seems to me that a useful legal theory could be pushed here in the civil courts. That is this:
If you deny your customers the right to carry when they otherwise have the right to do so, being licensed for CCW, you have implicitly taken responsibility for their defense. Therefore you can have the bejesus sued out of you if they are killed by some random massacre shooter when sufficient CCW density MIGHT have reduced the body count. Seems a clear case of negligence to me, assuming, of course that said theatre had no armed guards.
Could Cinemark be sued into oblivion over this issue and a head planted on a public pike for other businesses to see and reconsider similar policies?
That would be not letting the crisis go to waste.
Yes, you could say that the shooter was a Democrat, and probably a member of OWS and its more extreme fringes, and such might be a useful counter-narrative to push, and it is probably true.
It's also really fishy that the whole thing happens so close to a UN treaty signing on small arms, but advancing a theory that it is a false-flag conspiracy is also unlikely to be terribly useful.
But wouldn't it be better to put the ambulance chasers to work for a good cause?
Apparently lots of the population agrees with this sentiment, judged by their revealed preferences.