"Not sure what's with the downvote"
I'm about to disagree with you on a sensitive subject, so first let me say that you have my full sympathies and condolences for your loss. My disagreement has nothing to do with that and I sure as hell wouldn't downvote you for feeling the way you do.
I think it's your choice of where to place the blame. You're saying the clinic insisted your GF take that specific treatment and then didn't even complete the course, but you're apparently blaming the ket when it seems to me you should be blaming the clinic for not treating her properly. And you didn't say how she died, but again you're implying that it was the immediate result of taking ket rather than self-harm - although that's something of a moot point because either way it's still the fault of the clinic for not treating her properly. But despite your terrible experience ketamine therapy is a legitimate form of treatment. I have a friend who has been on the schedule for several years to treat similar mental health problems to your GF, and for her it works. It should not be dismissed out of hand because one doctor made an awful misjudgement in one case.
I agree with you completely on the general point, though. Ketamine is not a safe drug. It needs to be properly prescribed by qualified professionals and it has no business being advertised on social media. I hope Meta gets thoroughly clobbered for this.