There are multiple ways one might commit suicide, it is true. But some are more reliable than others; some leave a terrible mess for someone (perhaps a family member) to clean up; some are more painful than others; some may put other people at risk. The worst outcome is when a person tries to kill themselves and ends up alive but in an even worse condition.

For people who don't have religious prohibitions on suicide, having a reliable, simple, low cost, low-pain, low-mess option sounds great to me.