The statement is by and large true that religion is important to conservatives. That was my experience, as I made the transition from being an unbelieving liberal to a conservative Christian. As I became more conservative, I ran into more and more observant Jews and committed Christians, both among libertarians and among conservatives. And demographic polls bear this out.
Being a conservative is to recognize that certain truths are constant, and unlike the so-called principles of Leftists, these truths do not change depending on the context, or on whose ox is gored.
Being a Christian is the result of asking why the truth is unchanging. Most conservatives are religious because they sense that moral and ethical truth come from somewhere outside us—or rather, someone outside us.
"Ignorant" is not the word I'd use. "Generalizing" is the word I'd use.
Many conservatives are atheists. However, I find that the conservatives who are atheists tend to believe in the eternal truths. They may not call it "God", but these truths still serves as a permanent anchor. Conservative atheists almost always believe in a definite right and wrong and that humans have an obligation to do right regardless of the circumstances.
I considered bringing up conservative atheists in my original post, but it would have obscured the larger point I was trying to make. Please forgive me for my generalization.