In terms of religion, I'm not really an expert. Still- I imagine it's because religious folk maybe think we are here for a reason. They seem to have some masochistic idea that all this suffering is for something. After all- it must be God's intention. So- maybe they think we are just supposed to put up with it in order to learn some great lesson. A lot of religion and especially Christianity seems to be about obedience.
As to whether it's just as bad to think about it as to do it- I imagine the latter is worse. Feeling aroused by another person's spouse is different to having an affair with them. If we compare it to other so called sins- I think the idea is we may want desperately to do something 'bad' but we resist. We call on God or whatever to give us strength to do the 'right' thing.
It's kind of perverse when you think about it. We have been designed as lustful, gluttonous creatures but we are taught that both are wrong. A lot of religion seems to be about tempering our animalistic natures to enable a more 'civilised' society. Just like law really. Religion mirrors law in a lot of ways.
The cynical part of me has to wonder whether it is all just made up to control us... In which case- the REAL reason is probably money at the end of the day. I imagine it's more likely that the relatively poorer people of the world kill themselves the most. The super rich people in charge need those people alive in order to be able to exploit them!
If there is a God, are they REALLY that masochistic that they want us to prove our 'love' by doing or not doing the most horrendous things imaginable? Like asking Abraham to sacrifice his own son? Even as a prank or test of loyalty- that's pretty sick!
I think it would be fascinating to find out just how Christianity sees suicide from source material- not people's interpretations. But then- I suppose all of Christianity is an interpretation. Jesus didn't write the bible. I'm not so sure it is even categorically portrayed as a sin in the bible. I wish I could find it again but I can't... I once watched a YouTube video that claimed that the idea of suicide as a sin- punishable in hell came about at a specific point and for a specific reason. Back in the day, peasants breaking their backs on hard labour in the fields were told their reward would come in heaven. Supposedly- more and more decided to jump the queue and suicide. So- in response, this idea came about to put them off. Like I say though- I can't find the video now. I've never been able to find anything else to back it up either. I wonder if anyone else has heard this theory?