[Charlo]

Simply put, the "brony" fandom is very appealing to a certain segment of the population, and it's very easy to get into. All those other reasons such as "great storylines" and "hidden meanings" might hold true for a few individuals, but those reasons are secondary to the fact that people simply enjoy being part of a group. If the fandom didn't exist, there would be no reason to get deeply involved with the show; you might watch it and enjoy it, but you wouldn't go all-out with avatars and discussions and stuff.

The "brony" phenomenon has deservedly gotten a negative rep for the following reasons:

-Bronies post pony shit where it isn't needed or welcome
-Bronies have an annoying tendency to base their online identities around ponies, even on otherwise non-MLP-related communities (FFR being one example we can all relate to)
-Bronies, for some reason, make themselves very visible and thus, are an easier target than smaller but equally-annoying fanbases
-A few bronies display such ridiculous, awkward, and occasionally perverted behavior that they tarnish the whole community, most of whom are probably perfectly normal