Good point... From Wikipedia:
Doubt as a path towards (deeper) religious faith lies at the heart of the story of Saint Thomas the Apostle. Note in this respect the theological views of Georg Hermes:
... the starting-point and chief principle of every science, and hence of theology also, is not only methodical doubt, but positive doubt. One can believe only what one has perceived to be true from reasonable grounds, and consequently one must have the courage to continue doubting until one has found reliable grounds to satisfy the reason.[3]
When fundamentalists say there's no morality outside of the bible, I've tried telling them to look at certain parts of the Buddhist scriptures (which in my opinion covers some of the moral parts of religion without the blind belief parts). But it just seems to go over their head. Anything outside the bible is suspect. If it seems to contradict the bible, it must be devilish. Etc.
Not every religion has a Kalama Sutta (also known as "Buddha's charter of free inquiry").