Not to be mean or insensitive, but how is this not just the convenient avenue of the day?
Yes, it is exactly the convenient avenue of the day, and that's the problem. People who own a gun are eight times more likely to die of suicide than people who do not, simply because they have easy in-home access to the most effective tool for the job. People who live in "food deserts" have poorer diets than people who have convenient access to healthy food, because nobody wants to travel across town when they're hungry. People playing video games solve most of their in-game challenges through (virtual) violence, because violent actions are what the game designers have mapped to the most convenient and obvious game-controls, while non-violent solutions require a lot more thought and contrivance, if they even are possible at all.
Convenience matters, because people are more likely to do something when it's convenient than when isn't. So in this case, ChatGPT gives mentally marginal people convenient access to an encouraging, enabling, delusion-reinforcing "friend" 24/7 in their own home, for free, with insufficient guard rails, leading to the outcomes we see reported here.
It's incorrect to think that mentally ill people are doomed to madness no matter what, just as it's incorrect to think that people with weakened immune systems are doomed to die of infection. They have a higher risk, certainly, but whether they actually fall victim or not depends a lot on what's going on in their environment.