I'm kind of confused.... Is this post about the Big Brother/Big Sister program [which i haven't seen any subsequent posts discussing..] or the guy giving out free binders....
If its about the big brother program... then yea that sucks, but its rather easy to see that someone not on hormones (regardless of boobage or not) probably wouldn't be the best fit. Maybe if it wasn't gender specific (ie women could get paired with a little brother or little sister and visa versa) I could see the anger and frustration, but this all goes back to expecting the world to accept your mental image of yourself despite what everyone else sees. Most people in our society aren't good at looking at an apple, being told its really an orange, and then remembering it and accepting it as truth even though every time they look over they see an apple. Doesn't mean you wouldn't be a good mentor. In fact I think a lot of trans people would make better mentors. It just isn't the right program for you.
If this wasn't ever at all about that organization than I apologize, but thats the impression that I got from the OP despite the fact that no one else has seemed to mention this... maybe I'm sorely mistaken.
As for the program to give out free binders. I think he is doing an awesome thing despite any restrictions he may have. I understand why he does under 21 (even as someone over 21).
People under 21 are less likely to have not only the money/means to buy such a thing (credit card ect) as well as the parental support for such a purchase. A lot of people's credit cards go through their parents (mine did despite the fact that I paid it). Hell, my mom still looks at my credit card info online from time to time. Over the holiday she accused me of being an alcoholic because of it (while truthfully it turns out my card number had been stolen and the accusation was revoked with an apology)..
I'm certainly not saying that people over 21 are financially stable (or even that they should be [hell, I'm not]) but one can somewhat expect that when you're an adult you can manage to eek out the money for a binder in a semi reasonable time frame.... I mean the tri-top from underworks is only 30 dollars [disclaimer: I'm really not trying to insult anyone who couldn't manage 30 dollars for something. Thats f_cked up, and I've certainly had those moments.]