Coming from someone who so strongly advocates for gender equality and whatnot, or from anyone really, it seemed a pretty strange comment for several reasons, some of which I have explained below.
1) My friend said it in a harsh, derogatory way. Someone's gender expression should never be a cause for harassment.
2) She might have meant "butch" in that she sounds confident, in which case, that's a pretty crappy insult. "Haha, look at you, you're so confident!" If anything, that'd be a compliment. Isn't it great if a girl can feel confident, especially with so many stereotypes running through her head about what to wear, what she should look like, who she should talk with, ect?
3) I don't think, and I think many would agree with me here, that there is a specific kind of voice that goes along with being "butch," or anywhere along the lesbian spectrum. Some women have deeper voices than others, but that does not define their gender expression, identity, or sexual orientation. Or anything else, for that matter.
Anyway, my friend's comment, as you can see, got me thinking and really bothered me. After my other friend gently told her off, the first friend replied, "Well I'm part of that group, so I can make whatever jokes I want." I don't know about you, but that just seems kind of obnoxious to me. Even if she does identify as LGBTQ (which I don't actually know if she does) it shouldn't matter because that comment was derogatory no matter how you look at it. She was putting down a (quasi) friend of mine, women in general, and individuals who identify as butch lesbians themselves, and I don't think that's acceptable in the slightest.
Thus concludes my rambling for the day... Not that I post daily rambles. (As of yet.)