You pretty much summed up the whole of Christian history. It did borrow heavily from Paganism, the ends pretty much always justified the means, and though some say their actions are "anti-Christian" we can find Biblical evidence to support their claims. It's not even unusual for some to believe the Jews brought the Holocaust upon themselves, because just look at how God treats them in the Bible. Plus we have it straight from the horse's mouth that "Hey! I'm doing the Will of God!" It's almost like trying to diminish the Christian influence behind Mike Pence's RFRA. It's there. Get over it.
That he took advantage of Christianity when it was politically useful is very different from saying he was Christian-influenced.