I think its modern societies reluctance to acknowledge that death is a part of life (we're all scared of death to some degree). We evolved to think this way maybe due to our culture and history in the west, we think we'll always win wars and our history and philosophy shaped the idea that death is a bad word, meanwhile eastern thought and religions are much more open to the idea of the cycle of living and dieing.
Anyways, our modern society wants to keep it out of sight and not think about it (if someone dies, tape is put up, the cleaning crew comes and covers the body, puts it in a body bag, and it gets sent off to be turned into ashes before anyone sees it). Now we are even censoring death, you won't see stuff like uncensored Vietnam war footage on the news, they don't want sites like this to exist on the internet, its like you aren't even allowed to have thoughts of the fact that you will die one day.
We've also got an overabundance of food and technolodgy right now (none of these will last though) so we can live longer than ever before. Theres an illusion being created that nobody dies, all diseases can be cured and we will live on forever. Its a delusion that goes against the laws of nature, everything eventually has to die some day. The human race itself is going to go extinct. Thats just how it is, but some people really think that won't happen and will go to great length to not let that happen (even if it causes a massive amount of suffering and death to others!). Even if you weren't suicidal you have to think about death at some point, but people just don't want to. You can ask my parents, they're both over 70, physically and mentally falling apart but legtimately think they'll live on forever, divorce and start new families , making plans to buy new expensive homes and live in paradise despite them going into debt and causing a ton of trouble. its funny.