Frankly, I doubt that freedom has ever strengthened religion. Religions typically come into existence and become strong and resilient in times of of oppression, loss of infrastructure, loss of land, etc. Religions like western Christianity certainly grew and established themselves along with the rise of western nations, but they have become religions that cannot really survive without protection.

Religions are what bring people hope when nothing else brings hope. When government and other forms of power are on your side, your religious community will tend toward a social club or worship club or what have you.