Oh yay, another piece of dumb internet shit I need to explain.
"The Red Pill" is a meme used by men's right activitsts, the alt-right, and assorted other internet jackasses to describe an epiphany into the nature of our culture that they supposedly have.
The origin of the expression is from the movie The Matrix. If you want to have some fun, go and read the writeups under "The Matrix", most of which were written close to twenty years ago, about the weighty philosophical and social importance of "The Matrix". In order to get to the dismeaning of "The Red Pill", we have to summarize what the consensus view of The Matrix is: The Matrix was a film with innovative, stunning visual effects and fast paced storytelling to tell a story that was basically entry level concepts of Buddhism and Cartesian Doubt. It was a great film in 1999 and a good film now.
In the film, the hero is offered two pills, the blue pill and the red pill. The blue pill will return him to a state of acquiescence with the world he lives in, the red pill will make him realize that he actually lives in a gigantic computer simulation run by sentient AIs. In our world, people who believe in "the red pill" believe it means...well, I don't really even know...that once you believe in your inner alpha male, women will give up their manipulative ways and admit they find your cargo shorts overwhelmingly sexy. Or something.
The Wachowskis themselves are understandably a bit annoyed at the whole thing. For one thing, the Wachowskis are both transgender, so the idea that they made The Matrix as a metaphor for embracing traditional gender norms ludicrous. The politics of the Wachowskis, and the message of their movies, are basically emancipatory and in a liberal tradition.
Beyond that, for me, the idea of waking up to the world of contradictions around us is a complicated process. In the Matrix, because it was a stylish movie made in 1999, it was shortened to taking a single pill. The answers that "the red pill" offers to its conservative adherents are as entry level as the Gnosticism 101 of "The Matrix", but unfortunately, they are supposed to apply to the real world, instead of to Keanu Reeves doing Kung-Fu in cyberspace.
So now you know.