It's one guy. Who cares? Lots of individuals say pretty stupid stuff. Doesn't mean we should be making generalizations about an entire group of people.
Who's suggesting that we should make generalisations about an entire group of people? If you're looking at the OP, it doesn't say that Christians are at fault, it says that, because he's a Christian rather than a Muslim, the media is refusing to call it "terrorism". It's a criticism of the media.
The problem is, people are all too quick to make generalisations when it's a Muslim. One Muslim says something like this, they're immediately branded a terrorist worldwide (and rightly so, if they say something similar to this). But this guy is going to be pretty much ignored for saying it, because he's a Christian.