Uh, not really. If people weren't buying and using it, there would be no need for violent cartels to manufacture and sell it. Users are just fuel to the fire.
That's true from an idealistic point of view, but the reality is that no matter how many guilt trip ads are released, society as a whole is
never going to stop using cocaine. Hell, it costs $400 here in Australia for a cut to shit gram which might contain 200mg of
actual cocaine if you're lucky, and people still snort that shit up and go back to their dealer for more. Humans fucking love cocaine, that's just the way it is. And even if individual users here and there stop, the trade won't. It's impossible that ads such as these will stop the violence in Latin America (which, by the way, is as much about heroin/methamphetamine/marijuana as it is cocaine).
The flip side is that it
is realistic that changing laws could stop these violence. As society changes and progresses, it isn't outside the realms of probability that these drugs will be legalized and the black market starved out of existence. The politicians who support and continue to enforce these laws despite mounting evidence of the devastation they cause are the ones who could create change on a large scale that would actually save thousands of lives, but choose not to. They are the ones who choose to remain 'tough on drugs' and allow the black market to survive.
As such, it's proper to place the blame on those who have the realistic power to end the black market (the politicians), not on the end users, who have no realistic power to end the wider cocaine trade (and often no power to even end their own use: after all, one of the qualifiers for addiction is continued use despite negative consequences).
If the creators of these ads seriously wanted to save lives in Latin America, they'd target these adds at the politicians who allow the black market to thrive and the voters who keep them in power.