Not sure if he's Christian anymore. From Wikipedia:
However, Lambesis also stated on his Tumblr page, "Every year that I had put toward my degree in Religious Studies caused me to see the god of tradition and ritual that I grew up with as less and less of a probable truth. By the time I graduated, my entire concept of the divine had changed as I sought to reconcile spirituality and reason. The more I sought truth uncorrupted by years of religious history, the more I kept finding answers I didn’t want to find. Emotionally, it would have been easiest for me to just hold on to what I grew up believing, but mentally that wasn’t an option anymore."
Either way people can fuck up and make terrible mistakes. It doesn't make you a bad person. People who have met him say he is one of the nicest people they have met. I'm pretty shocked to hear this and hope it isn't true but it looks like it might be.