And your example is really weird and obscures what’s actually at issue. The difference in meaning between the words “bros” and “sissies” goes way beyond just a difference in gender. One is a common and generally affectionate term that men call each other when being friendly. The other is most often used as a misogynistic term to insult men by disparaging their masculinity.
I wanted to give a couple of other examples too, but that’s just what I thought of at the moment. “Hey guys” or “hey dudes” also works though.
That’s not an excuse to use the version of that phrase which misgenders someone.