It's their life, they have the facts, it's up to them.
What an incredibly selfish thing to say. Unless you're happy to get seriously ill and seek no medical treatment whatsoever then it's not just your life. What about the medical staff who are risking their lives treating people with the illness? Who are working 18 hour shifts?
I'm self-isolating so I can still go round to my parents and help them out (and stop them from killing each other). I know not everyone has the luxury of doing this but if you can work from home and don't have kids to look after then staying indoors is not exactly the biggest sacrifice in the world.