In recent years, a number of experts have drawn attention to how social media has become a breeding ground for hate speech. In this work, I examine an Instagram post made by a martial arts teacher, along with the respective comments, which contain expressions of gendered hate speech. The post was made in response to a YouTube interview, in which an elite athlete gave an account, framed by the interviewer and by some commentators as an account of sexual violence. Our focus is on language practices of a discriminatory nature against women, used in responsive actions to this report, published on Instagram, both by the teacher and by users who align and affiliate with him. Based on Membership Categorization Analysis (MCA), it was possible to demonstrate the crucial role played by categorization as a tool to produce gendered hate speech. In the corpus, categories that were historically used to attack, intimidate or exclude women were invoked, reinforcing the deification of men and the demonization of women. The analysis points to the need for a discussion about the liability of social media regarding the propagation of gendered hate speech and for the legal discussion about the criminalization of misogyny. The naturalization of these categories not only favors the silencing of women s voice, but also encourages the spread of violence against women in the real world, a reality in our daily lives.