The likelihood of the rock and the animal are incomparable, the variety of complexity at different scales, and the precision with which the structures are conserved between living examples, are a different thing. It's all a bit of a pointless case in establishing god or not though, because theists can just say god set things up to make lfe possible or inevitable, or intervened in some ineffable unevidencible way in the long chain of unlikely events that allowed life on Earth to begin.
The idea god was only involved in setting Creation in motion, and isn't around to respond to prayers, is associated with deism, and that deity often called 'the god of the philosophers', associated particularly with Spinoza.
Dystheism, the idea of an evil god, has a bigger following than most people realise. Zoroastrianism, as still practiced by Indian Parsis, holds that worldly matters involving sin and mortality are in the realm of Angra Mainyu or Ahriman, but we can access the transcendental realm of Ahura Mazda who governs light and potentiality. Mithraism and Manicheism were widespread and influentual traditions that built on Zoroastrian ideas. I think it can be argued Gnosticism is the inheritor in the West of this line of thinking, where the hidden supreme god is even more clearly juxtaposed with a lesser evil divinity responsible for material Creation, sometimes identified with the Christian deity.
Descartes in his Meditations goes through a process of attempting to describe from first principles why god is necessary, and must be good. It's hard not to look at his steps as motivated reasoning.
I would look at the idea of god being good as a being an effective pychotechnology. In life we face troubles, and attempt to learn from them and do better. If we choose to believe in a cosmos directed by a being aiming at that, we can focus on believing that whatever hardships we go through, however diffcult it is to imagine at the time, are directed towards some future good and so meant to provide some lesson or guidance. In Notre Dame De La Gard in Marseilles, sailors developed a tradition of praying in the worst of life-threatening storms, to the lady for intercession, and committing to live a more godly life and to having a painting of their ship made for the cathedral wall in thanks. That every wall is lined by paintings of boats makes quite an impression. But the sailors that died, have no paintings. John Newton who wrote Amazing Grace is an interesting example, he was a slaver who became an abolitionist, after praying for intervention when at sea in a severe storm, and asking for the chance to set his evil deeds right. Events spurred him to live up to his conscience, against the source of easy money that he knew having himself been enslaved at one time, the full consequence of. A view of the world that pushes us to listen to 'the still quiet voice' is a positive one I think, though all too often drowned out by louder and less wholesome voices that seem to dominate Christianity in practice.
The god of the Old Testament was vengeful, spiteful, jealous, and embodied all the negatives of Creation like floods and plagues, experienced as judgements. The idea of an all-good god is the influence of Greek philosophy. Discussed here: Is the problem of evil a strawman? I look at the Euthyphro Dilemma as the insight also from Greek thought, that enthrones reason above god/s. And as framing the necessary goodness of a deity as rooted in simply given all choices, what reasonable being would choose any other way to be. Evil, greed, malice, require a non-holistic approach, of impoverishing and damaging some for the benefit of others. Focused on all, on the whole picture, net good would seem to be the only logical choice.
