none of the reports I've seen say he is a practicing Christian

You miss this report?

http://www.nytimes.com/2015/11/29/us/robert-dear-suspect-in-colorado-killings-preferred-to-be-left-alone.html

The younger Mr. Dear was raised as a Baptist, Ms. Ross[his former wife] said in an interview in Goose Creek, S.C., where she now lives. He was religious but not a regular churchgoer, a believer but not one to harp on religion. "He believed wholeheartedly in the Bible," she said. "That's what he always said; he read it cover to cover to cover."