You will know a tree by the fruit that it bears.
I know many people who claim to be Christians that don't act like it. For example, John Kerry and Ted Kennedy are Catholic. Need I say more?
This is what we call circular logic. You claim people in New Orleans acted worse than people in Biloxi because they're not Christian, and then when it turns out there are a much higher percentage of Christians in Louisiana than Mississippi, you claim you can tell they're not Christian because of the way they behaved!
And you want to tell me how to teach science!