Even if he wasn't a True Christian (TM), he was operating under the ideology of abortion being wrong, which is something heavily pushed, but not strictly monitored, by Christians. Not all Christians but many of them, I've come to realize. The GOP probably considers itself Christian as well, even though I doubt even half truly are. True Christians (TM) nationwide have not denounced them, have they?
In my mind, when it comes to such violent acts perpetuated as a result of this mindset, silence is promotion. So I consider him Christian since no one else is really giving me a good reason not to.
Not to mention, people are so quick to paint all Muslims as just "terrorists waiting to happen", but when I apply that same brush to Christians suddenly they don't like that kind of treatment. I'm merely pointing out the double standard, really.
Also, maybe he wasn't a Christian. How many non-Christians, who lack a Christian upbringing, are going to believe you? Especially with how influential the GOP is? Are you starting to see the problem yet?