Alternatively, John Wick, and almost every other action movie, show us that violence - and killing people - is an effective and morally acceprable way of solving problems. The distinction between violence and torture depictions is not as obvious as you want it to be.
I don't think that's accurate. More like, John Wick implies that violence and murder of those above the law is an effective and morally acceptable way to solve the injustice they perpetrate. That's a much more reasonable position that will have plenty of people on both sides.
Spoiler warning:
I mean, yeah, there is some more food for thought in there :
-The violence endemic to the conflict between man and the system in which he operates: (Wick and the Continental)
-The face of violence embodied by the struggle between personal/professional loyalty: Wick, and the Manager of the Continental.
-The violent fruits of man's will to free himself of the constraints of a system designed specifically to constrain him: Wick's breaking of the code.
-The tendency of violence to beget and amplify itself in the absence of some braking force.
-That violence exists as a universal tool in the toolset of interpersonal conflict, and a view of the world if it were shaped around an organized deployment thereof outside of our current set of institutions that we entrust with controlling the application of violence.
C'mon though, let's not pretend the movie justifies anything. It's Art. It isn't there to be blamed as a causative factor, it's there to be appreciated and moved by. To make you think, feel, and give you a new perspective. If John Wick can be credibly pointed to as a causative factor of escalating violence, then clearly Andy Warhol caused obesity and consumerism with his soup can, Dali causes people to be tardy, Clive Cussler is a leading cause of totally badass and inexplicably effective oceanographer cum international crisis resolvers, H.G. Wells caused the atomic bomb, Orson Scott Card already laid out how we'll handle first contact, and Oscar Wilde created the surveillance hellscape in which we live.
We may be moved by what we see, but in the end it is we ourselves that are the causative factors. We react, we integrate, we sculpt spots for each other to settle into through what we knowingly and unknowingly do.
Does Art shape culture? Or culture shape Art? Are the Artists warning us of what is to come, or are they tangifying the steps in the direction society is already progressing towards? We can't say for certain, but in the absence of an authoritative answer, I'd wager there us a dynamic equilibrium at work that is starting to be compensated for, depending on where individual decisions of sentiment end up pointing.