The Impact Wrestling star made the accusation against the famed RS Friday, detailing what she says was an absolute tirade full of hateful language ... targeting her transgender identity. Shaw is a trans woman BTW, and came out as transgender last year at Pride Toronto.

Here's what she had to say about the interaction, which she says happened at WrestleCon Friday ... where Gisele was doing a signing. She writes, "I have been bullied all my life and have never stood up for myself because I’m scared that I would get beat up physically, mentally, or emotionally. The bullies in my life have always silenced me, but that ends today!"

Gisele goes on to say that, while walking to her table, she heard someone shouting, "you’re a man,” “you’re a dude,” “you’re a piece of trash,” “you are filth," and “get the f*** away from here." She didn't know who it was at first, but later says she heard it again -- and saw Steiner.

She says she confronted him about it on the spot -- saying, "Excuse me?" -- but claims he continued to tear her down in front of a lot of people ... including other wrestling talent.

She says other prominent stars were around, but didn't do anything about it. Gisele adds, "I am not writing this because I want sympathy. I am writing this because I am done being bullied to silence. Today is International Transgender Day of Visibility and I am standing up for myself and for other people who go through the exact same situation on a daily basis. I want everyone to know what kind of a deplorable person Rick Steiner is and that this cannot be tolerated. This keeps happening because people let it slide and do not take any action. If you do business with these types of people then I will not do business with you."

The official WrestleCon account apologized for what happened, specifically naming Shaw/the LGBT community -- but not saying Rick's name. They add, "The issue has been addressed and we hope the remainder of the convention can be a positive experience for all."