I think the question is what makes it Christian in character--so much so that the term should go in the style's name. We don't speak of Buddhist kung fu very often, though there's a strong historical connection, or of Shinto Iaido. Certainly he's free to name it as he likes, but if you can only put one adjective there, why is this the most apropos one? Is it marketing--trying to attract Christians, perhaps by sending a message that Christianity and the martial arts can mix to those who might think "turn the other cheek" precludes such study, or trying to indicate that the system is only for Christians (I've seen this), or trying to make clear that Christian philosophy infuses the system (not clear from the techniques in the clip)?