He's not selling the religion, he's selling products that may be of interest to Christians. There's a difference. The market for these products is pretty much people who already have religion or are looking for material to help them find their faith. That stuff isn't free and you can't just walk into a church and grab this stuff from the pews either, so it makes perfect sense for someone to sell it.
You'd hope that they wouldn't gouge prices, but since they're not the only store around that sells this kind of thing I wouldn't be too worried about that.
But of course you can have your opinion
This is just mine.
