It's not meant to be nasty at all. For Camus, that was philosophy concentrated down to a single sentence. Why do we keep on living? Especially if one has decided not to breed? What then, is the point of life?
You can ask any number of people who have chosen not to have kids - or any number of gay people, or people who were born sterile, or have otherwise lost the ability to have kids - this question. For many of them, the answer is "to enjoy it, and to be a positive influence in the lives of others".