There are times when people need to be held accountable. But sometimes even when people know all of that they still have trouble with the words of Jesus. It isn't easy to quit thinking in merely human terms and think the way God thinks. So if God acts this way when we are sinful and when we are ungrateful, it is the least we can do with one another. Our problem is that it is hard to think from a different perspective.
Charity begins at home.
Even sinners love those who love them. Yes, charity may begin at home, but unfortunately for some people charity also ends at home. If we do that we will not be able to love in the ways that Jesus is telling us to love in the gospel. God's love isn't fair. It is beyond fair.