That’s not what life is about in Christianity at all. Life is about choice in Christianity. Freedom. You can choose to live for yourself or for others, for the world. Dwelling on one’s suffering is a form of egoism that distances one from others and thus God. That’s why suicide is a sin in Christian theology, because it arises from individualism, which denies the Holy Spirit that comprises and composes us all. Asking “why don’t they have the right to kill themselves” is the wrong question from such a theological standpoint. The right question is “why aren’t we rushing to their aid, especially when we have the chance to prevent the type of suffering that would inspire such egoism.” That opportunity certainly won’t always exist, sometimes organisms just break, it’s just the risk of material existence, and coping with that powerlessness is also a part, no doubt the hardest part, of shedding ego.