It is true many Darwinian evolutionists are atheists who seek to eliminate God in favour of blind chance, but Intelligent Design wants to ignore the possibility of the evolution of complex biological systems because they are complex. Commonsense, it is said, dictates that complex patterns and structures must be the work of intelligent design.
Such "commonsense" is an offshoot of the mindset which has beset humanity since the days of Aristotle. Had we been conditioned over millennia to accept evolution we would see such complexity as a miracle of natural development, as many today now see the symmetry of fractals.
Intelligent Design is creationism in disguise which seeks to declare aspects of biology off limits for rational explanation. It also paints itself into a theological corner because the Intelligent Designer must also be the Flawed or Evil Designer, given the prevalence of vestigial, atavistic, and congenital abnormalities in nature. The attribution of such flaws to the operation of secondary causes in nature - natural selection - seems far more consonant with God's providential and permissive role in Catholic theology than that of a direct Designer as in Intelligent Design.
Properly understood, evolution does not deny God as metaphysical originator of the universe, always with the power to intervene in the laws of His creation, but merely claims that in the normal course of events, He operates within the framework of the laws He has created. Natural selection and quantum appear to be part of the provenance of those laws.
For these kinds of reasons, Pope John Paul called evolution "more than a theory". Prominent evolutionists such as S.J. Gould and Kenneth Miller see no necessary conflict between evolution and faith. Intelligent Design, on the other hand, looks suspiciously like Ockham's discredited voluntarism - the denial of the importance of secondary causes in nature.