If peaceful + reliable are your main goals, that's fine, but they aren't everyone's. Some people are angrier than they are weary or sad. As
@Mm80 notes, self-hatred may play a role. Many people here self-harm, so why would they choose a gentle sleepy-type exit? (Rhetorical question there - no need to respond.)
Of course you're free to comment as you like. But someone else's suicide isn't required to seem logical to you, just as no one here is going to try to convince you to use a guillotine if you don't want to.
Here's that old thread about what different methods express:
https://sanctioned-suicide.net/threads/methods-as-forms-of-expression.17321/