"AITA for making a scene at the birthday of a 'friend' that outed my sister?"

My sister was born as a male. We come from a conservative family so my sister had only been out to me. She made a friend in a drama club 2 years ago who is proudly out as a lesbian. She has an lgbtq activism club. So after a bad family dinner where our family was being all kinds of bigoted, she sought comfort with someone she thought she could trust. She came out to her friend "Rachel."

Rachel promised she was not gonna tell anyone. However Rachel told.... A lot of people. She outed my sister at a party. By saying that's my friend. SHE is trans. We also found out she had told her girlfriend ans some other of the drama people. No one knew and it spread like wildfire. It came back to our parents and they threatened to kick her out. (we have a contingency plan)

A few days later I was out with my bf at a restaurant were I run into her at the bathroom. She tried taking to me. I told her I didn't want to talk to a snake like her. She kept cornering me and saying "what did I do.. No tell me... What the hell dude. Why is your sister ignoring me ". I pushed by her and she was following me. So I turned around and I lost it.

I screamed at her how she ruined my sisters life, how her selfish actions made life dangerous for my sister to live at home. She said that it wasn't her fault that my parents were a$$holes and I said that she should be ashamed of herself and she doesn't deserve the title of activist because she is a disgrace to the community.

She was crying and we left. Later I got a call from her gf giving me grief and that if I wanted to confront her, to not do it in front of her friends at her birthday dinner. I didn't even want to confront her. I blew up when she kept probing me. But in the bathroom she told me it was her birthday and I got to wondering if I wasnt out of line? AITA?

Edit:

My sister has not transitioned. My parents did not know she is trans. Just because you haven't transitioned does not make you any less of a woman (in this case).

What do you think? AITA for how she handled this? This is what top commenters had to say:

BroadElderberry said:

NTA. "She said that it wasn't her fualt that my parents were a$$holes." No, it's not. But it is her fault that they found out, and that your sister was forced to make decisions in the heat of the moment instead of making them safely on their own terms. She put a member of her own community at risk due to her own flapping gums. If she's crying, it's because she feels appropriate guilt for her carelessness.

grendelone said:

NTA. She forced the time and place for the confrontation. And of course, outing someone without their knowledge or consent is horribly wrong. Of all people, "Rachel" should have known this.

StarkHelsing said:

NTA OP. Could you have handled it better? Yeah, but she was asking for it. She was the one who wanted to know and kept prodding you for an answer. An answer for which you delivered, and she didn't like the truth. If she didn't want her birthday ruined, then she shouldn't have opened those doors.

What she did is horrible; she put your sister in harm's way and refuses to accept she messed up. She deserved to be called out. You, however, OP, are an amazing person. Please do everything you can to support your sister. She's going to need everyone she can get. This 'Rachel' can F off. Your parents also suck.

OP responded:

Yeah we are trying. Rn we are trying to apply for something that allows her to receive money from the state for uni without our parents to have to fill out anything. And she is staying with a friend of mine because at home it's just not safe for her

And amonerin said:

NTA. As someone who is trans I think what you did was the right thing. Yelling at her on her birthday was an appropriate gift for someone who has put your sister in danger.

She later shared this update on the situation:

Thanks for the feedback. I do agree that I could have handled it better. Not for her but for the bystanders that literally didn't have anything to do with this. I will try to control myself more in the future lol.

Also my sister received a DM from the group that Rachel helped moderate. They apologized to her and said that Rachel claimed that my sister had given her permission to help her come out to the community.

They basically said that if things got worse they would help her raise money so that she could afford living somewhere till she gets on her feet and that if she needed help re: mental health they would help her find resources.

Also Rachel's name was deleted from the Instagram bio and their website deleted the picture. They have not made any kind of statement which I think is good, because that would bring even more attention to my sister.

Also: this was all greenlit by my sister.