I realize that what the OP wrote is real issue for some men, so I don’t want to minimize it. But as Sdbg said, it is a matter of being comfortable in one’s own skin. I will admit that I would be considered one of the lucky ones, because on most days I hang about 7 inches in the locker room. It is just my natural state. And that was what I was given; I didn’t do a damn thing to “earn” it.
However, there are lots of things that guys do to “earn” other respect in the locker room. Whether, it is your abs, weight loss, biceps or anything else that takes work or effort, these are things that garner my respect. In some cases, it could even just be an outstanding personality. Some men worry far too much about what is hanging between their legs and how it appears to others ( notice all the tugs to make it longer!), but fail to gain confidence from their many other fine attributes.
Again, I don’t mean to belittle the OP or any other person’s insecurities, but even as a gay man your total package of who you are or a particular attribute that you have worked on will gather more respect from me.