I think it is wisest to remember two things 1. when a character speaks, it is their views, not the authors and 2. that the wizarding community is bound to feel pretty uncomfortable about Christianity in general: the Bible says that people who use magic should be killed and, in the past thousand or so years, Christians have committed atrocity upon atrocity on those who they have thought to be witches. They have burnt them (a horrible, exceptionally painful death) and tortured them (and I'm not talking about a beating, I'm talking about really gruesome, vicious, humiliating abuse.) It would be exceptionally odd that if a culture who has been so denigrated was not rather scornful of the people who have long persecuted them.

I actually have nothing against Christians: Christianity is no worse than many religions and better than some. I think the ten commandments are a decent set of life rules and I think much of what was said by Jesus was wise and good. However, I will never except those parts of the bible which encourage intolerance and cruelty, i.e. homophobia.