I'm not sure how rhetorical your question is, but I'll answer it.
In my case, I know my people care about me a lot, and while most of them don't know about my CTB plans, I'm sure if they did, they'd have the freakout reaction you'd expect. It's sort of ingrained in society that suicide is a form of taboo, whether religiously, morally, or legislatively. A "suicidism" ideology is not something most people ever bother thinking about. Most assume that everyone wants to live by default, and running off of that assumption, they assume that not wanting to be alive is thereby something that needs to be "corrected" about the individual in question.
Of course, it goes without mentioning that this is a horrible way of thinking, much like how people assumed left-handedness was a type of disease 100 years ago, or even with homosexuality, which is very much a relevant issue to this day.
so to answer your question, is a mix of genuinely caring feeling and not wanting to lose a friend, and societal conditioning.