I think one might want to make a distinction between society's proclaimed statement that suicide is immoral and how it is biologically wired. If biologically, we are wired to perceive suicide as high-status and it causes obvious negative effects, especially to the community, then it makes sense that as a society we have evolved to proclaim it as low-status.

For example, Japan has one of the world's highest suicide rate. My guess is that it as Japan's society proclaims less than others that suicide is low-status. This might be part of causation architecture behind the high suicide rate.