What’s a red pill?
RED PILL.
Originates with the MATRIX film: “Take the Red Pill if you want to know the truth.”
To “Red Pill” someone is to expose them to reality in a shocking way so they see clearly the world around them.
This ex-Soviet “red pilled” the interviewers by speaking the truth to them.
After the ad you can see the MATRIX scene:
https://www.youtube.com/watch?v=zE7PKRjrid4
The red pill is a reference to the movie “The Matrix”. In it, the main character can choose the blue pill and remain in a dream world or take the red and learn the truth about reality.
To add to TigerClaws answer, the term is widely used on
https://www.reddit.com/r/The_Donald/