Hey there, this topic hasn't been touched for a bit so "insert 2 cents here..."
Alright first of all, I am one of the most open Bronies the world has seen. When I say this I mean that I wear the merchandise, thus making me easily identifiable as a brony. I love and tolerate everyone, even when it hurts. Then when I'm confronted by an IRL hater, I simply stick to my friendship cannon and let them say what they want... Then surprise surprise, I LISTEN. If someone has a problem with me then haters gonna hate. I have worked up the reputation I have by not hiding a thing and letting everyone have a chance to see the magic of friendship (Let it be known that I am in highschool and completely straight. Plus I don't feel any mental health issues. So be assured that I'm not stereotypical or crazy). By giving everyone a chance to see what a true brony is, I aim to represent the fandom for what it is at heart.
As for "closet" bronies whether by Jessper's definition or whatever comes to mind, I only have one thing to say. Do what you want.
If you feel more comfortable concealing your love for ponies, then by all means do so, but understand that if you don't think your friends would love and/or tolerate you for who you really are than maybe those aren't the kind of people you should associate yourself with. Remember that there is always people around who are suffering the same circumstances you are and if you open up, you may just find them. Just take comfort in the fact that I personally don't have any enemies (maybe people I dislike, but no enemies). Logic is a powerful weapon my friend, use it to your advantage.
When it comes to family, well... you only get one... If they don't like the person you are, what can they do? Thats right, they can't do anything! You are under your own control. Now I'm not saying be a rebel, I'm saying be happy. I mean hay, who knows. They might just accept your personality, for change is scary and it doesn't come easily... but it still comes.
Well it seems I'm out of pennies so if anypony wants some friendly advice or maybe just a chat, PM me. I'm usually on latenight weekends