One can't logically argue that because something highly improbable happens, some occult force had to make it happen that way. The genesis of life on earth certainly seem remarkable, all right. So does the genesis of water and clouds. Whatever their pretensions to objectivity, design theorists, like biblical creationists, are usually impelled by religious sensibilities. Why they should find the concept of a Designer comforting, rather than unsettling, is perhaps best explained by depth psychologists.
Nature is a huge killing field rocked by ceaseless internecine combat.
Living creatures spend much of their time ripping other creatures apart or trying to avoid being ripped. Billions of people have died agonizing deaths from genetic flaws subtly shrouded in the innermost recesses of their DNA molecules. The list of ailments that afflict humans and other animals is longer than an anaconda. No human imagination is capacious enough to grasp the quantity of excruciating pain that animals, including humans, have endured, generation after generation, throughout what Shakespeare called the dark and backward abysm of time. The concept of Design raises more questions than it answers.