Not everyone is the same. I felt similar to you. Or rather, still do. But I've witnessed other suicidal people who seem to respond to stuff like that. So I guess it's better than nothing.
The problem is, people have a natural inclination to not allow suicide and try to stop you, but most aren't equipped to do so. So they try to offer help but it doesn't work because they don't know the problem. Or, in their desperation to stop you, they make things worse. It's a catch 22. I remember thinking that the worst mistake I made was seeking help by revealing my suicidal thoughts. Because after that, people no longer treat you like your sane. You feel like they'll just say or do whatever it takes to get you in a hospital or something and aren't actually listening.
But sometimes they're right. Other times you just have to be careful who you talk to. I think a stranger is too risky. I personally had to find someone I knew had enough experience with such situations that he wouldn't just panic and would actually be able to listen to what I saying.