People are limited by their own experiences. Furthermore, people tend to believe they are the heroes of their own stories. The person who asks you to be brave and choose life believes themself to be brave by choosing life. They see their own struggles in life and they've persisted. Why can't you? And they want to live, so living is definitely the goal that everyone should have, in their mind anyway.
Humans seem to be wired this way. Our obsession with living long lives has always perplexed me. I have never wanted to live past 50. I've been open about this to just about everyone. They dismiss it as a joke. They think I'm being funny because I'm usually funny in social situations. (Probably hard for you on SS to believe, since I'm usually so depressing on here!)