[The Old] Red-Pill (Urban Dictionary) 

Red pill' has become a popular phrase among cyberculture and signifies a free-thinking attitude, and a waking up from a "normal" life of sloth and ignorance. Red pills prefer the truth, no matter how gritty and painful it may be.

These men accept the truth and move through life with a new-found adapted mindset of human nature

[The New] Red-Pill 

Red pill is a community of misogynist that sit around complaining about how women are evil and incapable of valuing a 'good' man. In reality, these men are simply heart-broken and have no understanding of female-nature.