It is more than just a meme:

The fetish of cuckolding – where men allow other men to have sexual relationships with their wives – is on the rise. The cause of the rise isn’t clear, but psychologists have suggested everything from repressed male bisexuality to men being proud of their wives’ liberated sexuality. Online communities dedicated to the topic are booming, with Google searches for the fetish peaking this week, having more than doubled in the past 12 years.

Again, in r-selection the drive to monogamy fades. Additionally, I would imagine having first access to a mate that is banging everyone will produce offspring who will bang everyone, and that is probably advantageous too.

Notice the change in culture as well. In ancient Rome, this would have been cheered. In the 1950’s it could not even be mentioned in the media. Now we are back to cheering, but it will go back the other way again.

This is probably also related to Cuckservatism, all joking aside. The lack of territoriality, the lack of any desire to protect, the active desire to perform the sacrifice, the delusion that the sacrifice makes one somehow superior – these all likely run along the same neural circuits. Erode the amygdala with ease, and you get this moral deformity. Strengthen it with hardship and sacrifice, and you get the exact opposite.

Of course deep down, all rabbits, be they cuckold fetishists or Cuckservatives, deep down know they are wrong, because everyone knows, mankind was designed to be K-selected. It is why the ridicule stings. Ridicule Arnold Schwarzenegger for having been huge, and he would ignore you. Ridicule Donald Trump for being a successful businessman and rich, and he would ridicule you back, amused. Ridicule a cuck of any stripe, and they will whine and cry about how awful the label is and how awful you are for using it, as they fume, enraged.

They rage because, they know they are wrong.

People love to be told about r/K Theory, because even the cuckoldists know they are wrong