I would reject the premise. Historically, far more (and far greater) “intellectuals” have been theists and atheists or agnostics. The problem here lies in our modern tendency to equate “intellectual” with the sciences. Empirical science demands methodical doubt (the opposite, in some ways, of Faith) and cannot address the reality (or unreality) of the supernatural, as it is intrinsically confined to the study of nature. Hubris leads many scientists into scientism, the self-referentially incoherent philosophy that all knowledge or all certain knowledge can only be attained through empirical science. Scientism goes hand in hand with naturalism and materialism, which, in turn, lead to atheism (or agnosticism). Thus, those “intellectuals” that follow this path will end up atheists not because it is the “smart” thing, but because their a priori assumptions demand it.
Lastly, even if all “intellectuals” were really atheists that would no more prove atheism than all “intellectuals” once believing the Earth remained still was evidence that such was true.