"It's selfish", is something I've heard just about as often as what you've brought up here. I agree with you, but I suppose I have to be honest and say I see both sides.
Being someone that has attempted to/wants to take my own life, I see the view that believes it's terrifying and very tough to desire because of the stigma.
Then there's family. Always someone that loves you and can't stand the idea of Earth without you. "Why would you leave me here like this? Why would you do this to me?" Y'know the deal. Me being.. well not a completely heartless fuck, I have to understand and sympathize with that side as well. I would hate knowing someone I love is in so much pain they can't handle it anymore.. but like I said (ya, I know, sorry. Fickle.) I would understand. I would think they've been so strong for so long. I'd love them and support them, anyways.
If someone has really fought as long and as hard as they can, just to see if they can make it through, and they can't.. I can't tell them no. I can't stop them from the only relief they'll ever feel.