What does "take the red pill" mean?

It's really big in anti-feminist/MRA circles specifically, but it's also an expression used by skeptics and conspiracy theorists all over the political spectrum to mean "stop believing this one big lie that the mainstream establishment keeps pushing."

Conservatives:

See? He used a red rose emoji, that's a socialist symbol! Never mind the fact that countless other people use that symbol all the time, this proves he's actually a socialist after all, just like all the other cosmopolitan elites! The whole idea of "woke capitalism" is a lie, none of those people are really capitalists!

Leftists:

See? He's clearly pandering to misogynists, the "Red Pill" metaphor is used by Men's Rights Activists and other anti-feminist groups! Never mind the fact that countless other people use that metaphor all the time, this proves that he's actually a conservative reactionary after all, just like all the other corporate elites! The whole idea of "woke capitalism" is a lie, none of those people are really progressive on social issues!

Me:

Dude, it's pretty clear from context that he's talking about COVID-19. He's saying the coronavirus threat has been overhyped by the media and that the lockdowns are just an excuse to justify authoritarian government policies. Which is a really shitty take, admittedly, but it has nothing to do with socialism or MRAs or any of the other boogaboos that people keep bringing up. Stop letting your Outgroup Homogenity Bias show so hard.

A conservatarian take?

The fact that so many people on the left were so quick to believe he's suddenly become an MRA - despite the fact that he's consistently been supportive of women's rights and LGBTQ rights, and that the posts in question had nothing to do with feminism and gender issues - displays a certain degree of "all my enemies are basically the same" logic.

That's what is meant by Outgroup Homogenity Bias, it's the same type of thinking that makes conservatives believe that George Soros is somehow a socialist. It's like those old Jack Chick comics where Islam, Wicca, LeVeyan Satanism, atheism, capitalism, and communism were all created by the Catholic Church; there's this inability to understand that groups you oppose might oppose each other just as much as they oppose you.