The red pill
Netflix broke down so many of the allegorical references, including Keanu Reeves' character Neo taking on a new name and subsequently renounces his deadname. It also speaks about the red pill/blue pill dichotomy serving as a metaphor for estrogen hormone therapy, which Chu points out was literally a red pill in the 1990's.
Despite the narrative of the film being loaded with trans subtext, the "red pill" has taken on a vastly different meaning online, especially in terms of men's rights activists. The term was originally used to describe people who were aware of the "unpleasant truths" of the world, but it has widely been used by conspiracy theorists and subsequently, the men's rights movement. According to The Guardian in 2016, the "truth" that men's rights activists have supposedly been awakened to is a world dominated by women, where men can't express their issues without fear of retribution. To put it simply, the average Red-piller thinks, "Feminism: bad." The term was popular amongst men's rights activists and birthed the subreddit r/TheRedPill in 2012. Vulture reported that sexual frustration is also a driving force for red-pillers' vehement anti-feminism beliefs.
The red pill has also been taken on by the alt-right, as well as conspiracy theorists and white supremacists, according to New York Magazine. Each group's version of taking the red pill serves as a metaphor for being indoctrinated into whatever beliefs they hold.
Obviously, the hormone therapy subtext in The Matrix does some undermining of The Red Pill's beliefs. Even Wachowski has denounced prominent people using the meme. When Tesla founder Elon Musk tweeted the phrase, "take the red pill," and Ivanka Trump quote-tweeted it with "Taken," Wachowski responded, "[Fuck] both of you." While Trump and Musk did not express which brand of red pill they subscribed to, Wachowski's denouncement is telling.