They want this. This is part of their strategy.
A free people has got to be a responsible people. Freedom doesn't work if a significant percentage of the population are irresponsible.
The left has hit on this as one of their strategies: break down everything in society, every societal construct, that helps to foster responsibility, to build responsible citizens and reward responsible citizenship. This is one of the things that's behind the dumping of millions of mental cases on the streets, to make mayhem along with millions of illiterate illegal immigrants from the third world.
Break down the will of society to say "this isn't right." Make the whole concept of "right and wrong" sound anachronistic, bigoted, an artificial construct of dead white men to perpetuate a discredited system of privledge and oppression.
When one of these benighted individuals finally goes bonkers with a gun, if the pieces of the situation fall into place the right way, the left is there, with the narrative already planned out, the whole machinery of deception and propaganda is prepared for instant action.
They couldn't do it with Amy Bishop, or Fort Hood, or the Virginia Tech massacre, for a number of reasons. But they could do it here, and they have.
Thanks for your response.