Society can be a strange thing. I grew up in another country, and a part of that country, where women breast-feeding their infants in public was a normal thing, and nobody gave it a second thought. They weren't discrete about it either, and it was common to see a huge breast out there, laid bare for all to see, the whole thing, even the nipple if the child "unlatched" for a breather and then went back on after half a minute of looking around. Here in the States, for the first 25 years of sports bras' existence, they were strictly undergarments, and were absolutely to be concealed. Then, in 2001 IIRC, that soccer player threw off her jersey in celebration of a victory at the end of the game, exposing her atrociously fitting sports bra for all the world to see on TV, and women suddenly felt liberated from the forced hush-hush. Today sports bras are accepted as outerwear in public, and even non-sports bras are hardly hidden anymore, in fact sometimes they're flaunted.
Women wearing sports bras will always be more common than men wearing bras of any kind to remedy the problems brought on by breasts that resulted from hormones gone awry; but I still hope there will be a day when society comes to accept it. What causes acceptance, and what causes rejection, ridicule, whispers, wide eyes, and mothers trying to divert their children's eyes? In the country where I grew up, kids also poked fun at other kids who wore glasses. I needed glasses myself as a kid. I remember some whose vision was absolutely terrible but they wouldn't admit they needed glasses. One girl had to get right up to the chalk board in class to copy things into her notebook. "No, I can see just fine. I just do better up here." The front row of desks wasn't nearly close enough for her. Why the shame, when there was a legitimate need? I really don't know.
Since having my own problem and researching it, including finding this forum, I have noticed other men's breasts a lot more. I ride bicycle a lot, and last week I saw a youngish man riding shirtless, with breasts that were hanging down more than two inches, maybe close to three. In our society, somehow it's not acceptable to put a bra on them.
Part of the problem is undoubtedly that part of bras' designs is not just for function but for sexualizing women, and also that many women enjoy lingerie that's pretty and sexy, even if they would never show it off. For puberty-age girls, or even a little pre-puberty, there's a desire to identify as more grown up, so they want a bra before there's even any soreness or irritation to relive, let alone any unsightly shape to remedy. I'm sure we on this forum can identify with the need for such relief better than they.
The path to acceptance and understanding will be long, but hopefully we'll get there.