In any large group there are bound to be deviants that stray from their predetermined set of morals. Look at any religion, fanbase, or group that shares a particular interest and you're bound to find the idiotic loudmouths as well as intelligent people that we can trust (save politicians).
Odd, I think that most of us find the opposite to be true. Take a look all the posts available on the internet that cry abuse from their affiliates because of their association with a certain show. A significant portion of these attacks seem to come from the brony being obsessive to the point where it is annoying and has nothing to do with the non-brony's stance on the show; this is a small amount of our fanbase, but that brings me to my previous point.
It is human nature to find negative things to be more memorable than positive. A psychology paper I read claimed that "the brain handles positive and negative information in different hemispheres" and that negative thoughts require more thought than positive ones. I can give an infinite amount of examples pertaining to this but I will end it here.
I do apologize if you think that this was an asinine and irrelevant reply to an otherwise sincere question. I do hope that this all works out.