I'm just reading over what Aiden and Dan said about being or feeling like a boy. You guys are young enough that you might be able to go through a boy-to-man process, even if it's unconventional and somewhat delayed. Seems to me that it's perfectly normal for a twentysomething transguy to still feel like a boy in many ways.
On the other hand, a person can be much older than late teens/early twenties and still feel like a boy. I sure as heck do, and I generally refer to myself as a guy or a boy rather than a man. For a number of reasons, I've always felt that at least a part of me was perpetually frozen at thirteen. Considering my biological age and how long I've felt this way, I've probably been warped for life by this perception. Anyway, I honestly don't see myself as a man, and I'm not sure that I ever will. I'll have to wait and see.
I do, however, live by the creed of personal responsibility and, in most respects, I live as an adult.
I'm not always comfortable with these apparent contradictions, but they're what I have to work with.
Dan, many of the tough-guy effects that you're seeing are undoubtedly due to insecurity and essentialism, but let's go back to that "boy" concept again. If you're mostly talking about transmen who are in transition or transmen who haven't been post-transition for very long, think of them as still going through their boy phase. A lot of cisgender boys and young men go through similar phases of one-upmanship, hypermasculinity, and proving themselves--proving themselves to other guys and also to themselves. They are still situating themselves in (for lack of a better term) male society and society in general. I know you get tired of the "posing" that some transmen seem to do, and I definitely hear where you're coming from. It can be maddening.
But try to cut them a break, at least mentally. Some of them are probably trying to compensate for a boyhood that they never had, and most of them are probably still figuring out where they fit in the world. Maybe they'll settle down a bit later as they figure things out. Maybe not. But you're you and they're they. You might never see eye to eye. At least, that's my take on it.
If people hassle you because they don't think you're masculine enough or if they say that you're not a real man, then maybe that's all part of the boy culture that they're indulging in. Of course, that doesn't make it RIGHT...all you can do is stand your ground, be your own man, and lead by example--and air your views as persuasively as possible.