I've watched and enjoyed every episode of Friendship is Magic and post periodically in the MLP community thread on GAF... but I don't identify as being a brony. Why is this exactly? Well, let me tell you.
I have countless interests that I'm passionate about now or have been in the past. I'm a movie buff. I'm into fantasy football. I'm a Simpsons nerd. I'm a reality TV junkie. I'm passionate about gaming and have worked in the industry. I'm a diehard sports fan of multiple teams. I'm a voice acting enthusiast. I've been a wrestling mark. I'm devoted to my job, my family and my friends.
I don't identify as any single one of these things because I'm a complex human being and, frankly, you'd have a hard time pegging me for any one of them in public except for the fact that you might see me wearing a baseball cap for one of my favorite sports franchises. I use my interests to build common ground with people in any walk of life to have conversations and make connections.
There's nothing wrong with being passionate about a hobby. Goodness knows we all are to some extent... we're posting in the most diehard of gaming forums right now. But identifying as any one single thing probably isn't healthy. Friendship is Magic won't last forever. Broadening one's horizons is always a good thing. And it's never cool to force your interests on others while ignoring any and all social cues... and I don't care whether that interest is My Little Pony, your political affiliation, your religion or anything else. Just have respect for your fellow man and, frankly, you can indulge your free time with any hobby your heart desires and I won't judge you for it.