I disagree with that conclusion, as I stated in some other post with a similiar topic, most religions have no opinion or are supportive of suicide in certain conditions. Jesus for example, essentially commited suicide-by-cop, and is worshipped for it. The bible also doesn't have any explicit text condemning suicide, some people choose to interpret it that way, some don't.
There are thousands of religions today, there were likely 10s of thousands before European colonialism wiped out most of them. To blame religion for western culture's (mainly the US) views on society is intellectually lazy at best, if not outright wrong.
I think suicide why suicide is frowned upon in western culture is largely due to fundamental philosophical beliefs made by influential intellectuals. Namely the belief that an individual owes their life to others, not themselves. It is a core principle in feudal society's social contract between the state, private, and public sector. These feudal principles weren't challenged until the enlightment era, which has taken that whole subject matter into a different direction (ie capitalism).
Unlike in feudal society where every citizen has a purpose in society from king to slave, even if it was a shitty life, it's believed people's lives have inherent value. In a capitalist society, human live is inherently worthless, your value as a person is determined by the market. If you don't generate profit, we as a society will leave you for dead. That's a large (and rather regressive) change in philosophy, and we can see how it's implementation has affected the social contract between state, private, and public interest.
Because profit-making is a virtue, poverty is a sin. But not a sin against god or the common good, it's a sin against the market. Our current society founded on the premise of "individualism" is incapable of accepting suicide because suicide, or more specifically the act of "self-sacrifice", undermines markets. Therefore it is irrational and immoral behavior only capable of being perpetrated by the most vile and ammoral characters in society. We're not supposed to care about our personal relationships with others (or lack of), we're supposed to compete, swindle, and exploit them.
I could go on, but this essay would turn into a thesis.