This is probably the most profound thing I've read in a while.
But seriously, I think people care. I care about my friends and their lives. I bet there is at least one person in the world you care for. Understand that people do care about you but we are selfish creatures. We can't inhabit the minds of others - only ourselves. That creates a dissonance between the thoughts and feelings of other people and our own self. It's fucking scary to me too, though. Yet, we can't truly understand anyone but ourself. And sometimes even that fails.
I would say though that most suicidal people I have encountered in life (like I would say myself too) care more about other people than most. I think it's because we want to shield them from what we feel. I'd die a gruesome, painful, death for my friends, friends that I doubt even enjoy my company, to never experience the self-hatred that I feel. That's the beauty of this community - likeminded people to express ourselves with in a world that simply doesn't understand people like us. The possibility to support and be supported by people who at the very least share a similar experience to you.