I think slang terms for referring to a person in conversation (like dude and mang) should be considered gender neutral. My reasoning has to do with my understanding of the subculture those terms come from.
I was designated driver for my stoner friends and thus, can legitimately pull off using the word “dude” in casual conversation. I would never say “dudette” because that would be disingenuous and if I had said that around my stoner friends I would have been laughed at as a poser. Only squares who don’t get it would ever say “dudette”, like in Disney’s “The Goofy Movie.” Calling a girl “dudette” would would mean pointing out how she’s different from the boys in the room and thinking about all that’s just gonna break my chill. That is, disrupt the positive atmosphere of the group and make it difficult to enjoy the moment.
Use of the word “dude” to refer to both girls and boys was actually an egalitarian linguistic norm. It didn’t erase the experience or presence of femme people. Trust me, you get a bunch of teens in a room smoking pot they’re gonna know exactly who the girls in the room are. There were multiple occasions where we were dividing up into teams for a game and someone said something like “boys vs girls is three on three,” only to be corrected that “Kim’s not actually a chick, he just acts like one.” I was still closeted back then so, accurate. My point being that because the word “dude” is gender neutral in the subculture it comes from and is only given a gendered perception in mainstream culture thus, it should be considered gender neutral.
Furthermore, from being in community with people from the structured gang culture it has become apparent to me that the word “man” has similar usage, though different connotation. In fact, in the structured gang culture, for a girl to be called a “mang” as opposed to being called a “bitch” would be a recognition of her strength and humanity. However, once again, the mainstream perception of the word comes with masculine overtones.
I cannot speak to other slang terms that have similar usage because I have not been in community with people from those communities. To come to a conclusion about the word “brah” I would have to spend way more time around weight lifters than I think would be (strictly speaking) good for my girlish figure. I would not be surprised to find a similar pattern there.
Rednecks (which I are one) get off easy. The closest we come to having a term like “dude” is an inarticulate grunt. And the next closest term is “ya’ll” (which my spell checker wants to spell wrong by putting the apostrophe after the “y”). Both are seen as gender neutral. In fact, quite a few redneck terms have made their way into the speech of people in queer communities. Such as folk, ya’ll, sorted and figger. As in “many folk figger I’m an effeminate gay guy, when I’m actually a trans gal. Usually, a quiet conversation gets that sorted.”
This has lead me to think about how queer people interact with the subcultures we come from, what we bring with us into our new communities when we leave our old selves behind, and how we navigate what other people bring to those communities.
It is said that, in the process of colonization the first thing to go is language. So what does it say if we erase the way people talk? Especially when if we took the time to properly understand what is being said, we realize that we would be ok with that language had we grown up with or lived in that culture.
As a trans person, I want people to recognize and respect my desire to be treated as the woman I am, and as a feminist I want all women to be treated with positive regard within their own cultures. So what does it say if I reject being treated the way a person would treat a woman positively in their own culture and attempt to impose my concept of how a femme person is to be treated in queer culture? Seems colonize-y to me.