Interesting analysis indeed that make me review my position a bit.

Where the article is right, is that we know very little about suicide, depression, and cognitive dysfunction in general. As it says, the only prevention method we currently have is basically asking "do you plan to kill yourself ?". There are some protocol that can estimate the risk level like asking "have you ever consider it before", "how many time in the last 2 weeks", "have you ever thought about scenario", "have you ever tried it", etc... But some people may "simulate" suicide attempt dozen of time to ask for help, whereas other will kill themselves at first try without any prior sign.

Lonely person may find refuge in LLM which may end up in a deadly trap. Like he could have ended up in MMO game, social networking or anything else that could lead to the same consequences. I just find too easy to blame AI because it's a new way to lost itself. But where you are right, is that we could expect a human community to be naturally kind (most of the time...), whereas LLM doesn't even understand the idea of kindness.

Then, suicide and depression is not always due to social or environmental causes. Sometime, it's cause by chemical unbalanced in brain. In that case, there is no psychological treatment and the only solution is medication (in current state of science).