I am not entirely sure, I have not seen any statistics on this one so it's difficult for me to know how many Christians there are who happen to also like MLP, while I am not Christian myself, I think I can see some parallels with that and the storytelling of MLP FIM although the religion itself has nothing to do with MLP. Even an agnostic like myself would struggle with publicly letting everyone know I like MLP by real name, because it comes with a stigma that is not deserved, sure, you get some hateful people in the Brony and Pegasister community still, but it is not as widespread as some would have you believe, in fact I have found more caring and considerate people in this community than anywhere else I've looked, when we're feeling down about something, there's other's to lift our spirits, no pun intended, basically what I'm saying is, this community finds strength in numbers and providing a support network, not putting other's down, the behavior I would come to expect from individuals who wish to share the ideals in the fictional world Equestria, and I also regret some negative things I have said about MLP fans in the past.
I'm not joking when I say this, this community may have just saved my life when I was going through some mental health problems, and still am though I find coping mechanisms like anyone else.