Neglecting to make a choice is a choice in itself. Camus was a nihilist and believed life to be a futile burden. And ultimately it is, as far as we know. He’s giving an incredibly optimistic nod to the “absurdity” of living to justify attempting to maintain a passion through it without subscribing to the Kantian ideas of pure reason. The implications behind the contented Sisyphus is that he allows himself to forgets that there is no meaning to life by giving into facade of the great play.