@ajddavid452 First of all, I apologize. I didn't mean to offend you and you're 100% valid.
I've been in both the online trans identity/gender-transformation fetish community (surprising amount of overlap there) for the last twenty years and I have never, word for word, heard the phrase "did you just assume my gender?!". I have heard more than once "why are you assuming I'm X ?" but that's a very different phrase since it's not calling out someone directly.
Sorry if I seem a bit bent out of shape over that but I'm frequently seeing that "did you just assume my gender?!!" thing as a way of very subtly trying to shame people for wanting to self-identify. One of those cultural jimmy bars that bad actors use where if you try to call it out, you get "it was just a joke, chill bro!". (somehow these same people don't seem to realize a joke isn't funny after being repeated literally hundreds of times. I'm not sure that one was ever meant to be funny, though, thinking about it)
Anyways, I know you were only using the phrase ironically, so I thought not to make a big deal of it. I've been trying to pick fewer (but more meaningful) battles on Mangadex. Instead I thought I'd just make a joke too to show we were on the same level. An obnoxious ironic comment, about the story's magical girl app and gender fluidity it'd allow if it was real. But I wasn't looking to upset or offend you.
Again, sorry.