It's also really easy to screw it up, and many people do, some even after many attempts.

Not everybody is super diligent in researching the most effective methods, and some people may be genuine in their desire to die but are impulsive about it so may not choose the most effective method in their desperation to kill themselves now.

I'm not sure if we as outsiders are in any position to judge the sincerity of another's wish to die.