Not all Christians act that way, and not all Bronies are friendly either. I'm a Christian and I do try my best to do good, but of course I'm not perfect either. On the other hand, there are people who are "Christians" and don't act like it at all. Sometimes people are younger and need to grow up and learn what's right, but still not an excuse for them to do bad things.
For Bronies, there have actually been some really rude ones out there, and of course, I've met mostly nice ones (Thank God). But yeah, just because they watch a show about friendship doesn't mean they'll always be nice.