They can’t access the feeling of contentment and charity without someone instructing them to it – or they think they can’t. The idea of loss of this life comfort is terrifying (“what if it goes away when god goes away?”). The step is huge, the chasm is black and deep to them. So the cost of hanging on to the belief in something they don’t bother prove is much less troublesome than the feared cost of what they think they will lose by exploring that proof.
But what if the goal is to achieve as much contentment and feelings of charity as possible? Given that question, ss theism a rational belief or not? I don't think atheists are superior people in any way to theists. We've just somewhat different interests and therefore have received the necessary tools to successfully argue for god's improbability. But are we because of this more content?
That is my husband's argument for why Religion should not be mocked. If those people need that to be decent, why take it away? They might stop being decent. My take is that their fear is unfounded and they will actually continue to be decent once their god belief is gone.
We haven't settled the truth of those positions yet...