This human form is merely a circumstance that has been met with, just something stumbled into, but those who have become humans delight in it nonetheless.
(Zhuangzi, 6:28; Ziporyn)
It all just happens, without intention, without purpose, without any reason why. This at least is how things so appear to the philosophical Daoist, and though he would not wish to make of it a dogma, he takes it as the apparent reality that informs his living. We might say that Zhuangzi was not burdened by a theist enculturation that rendered such an outlook less obvious to him than it may to us. Weighing the two, I myself see how the theist thesis clearly "adds something to the process of life" in as much is answers psychological needs that are themselves in apparent disaccord with the way things are. Then there is the simple fact that "God" is a great idea except in that it is always just an idea that falls infinitely short in every way of what God would have to be. Every God-concept, by whatever name, is a form of idolatry. Let there be God; only let us truly honor it in understanding that it is Utter Mystery and not assign it personality, moral concerns, intentional dabbling, and other absurdly limiting anthropomorphisms.
Our lives just happen, apparently without rhyme or reason, and that is part of the Mystery that teaches us. Existentialism, bound by the rationalism it purported to dismiss, typically took this as an occasion to despair, but for philosophical Daoism it is an occasion for thankfulness and trust. "We delight in it nonetheless"; all of us. Thus, to delight in this experience of having a human form is living life as life lives us. It adds nothing to the process of life. It is in harmony with the life experience.
The more we can delight in life, the more authentically we allow the life experience to manifest itself in us. Releasing ourselves into vastness is all about affirmation, and nothing about negation. All is included, nothing is rejected.
You can check out Scott's writings on Zhuangzi here.