Also social pressure and expectations. How many people would feel comfortable saying "Sorry mom/dad/friend/potential partner, I'm not going to have kids because I'm worried I might not be a good parent or maybe even take my own life"?
From my experience, it seems there is a good reason for the stigma. Depressed people with pessimistic worldviews don't make good friends. The worst time for me to make friends is when I need other people the most (such as when I'm depressed), but when I don't need people my interest in them becomes almost nil.
Also, I highly empathize with the idea that when the fear of failure can be linked to the risk of one's life spiraling out of control potentially all the way to suicide, whether or not those consequences logically follow, it takes away a lot of options that might sound common-sense to someone of a healthy mind (aiming for challenging side projects, putting yourself in front of others). For such people, I believe shielding yourself from those signals is a valid option for survival, even if it means having to deceive yourself temporarily.
Doesn't help that all your mrs's intsa-friends are posting bollocks about how great everything is while you've been trying to get your newborn out for a walk for 5 hours and failed.. heh.
Don't overthink that stuff though.. I mean, you kinda know deep down if you've got it in you or not. It's kinda like having a puppy times a million..
That ended our relationship. I think it was good to be up-front about it.