#EatTheRich is not a campaign as such, but a slogan with a long history which has recently been appropriated by protestors against Wall Street.
The phrase "EatTheRich" has been used in protests against income inequality the US for a long time. The phrase 'Eat the rich!' is believed to be coined in the 18th-century by French social theorist Jeanne Jacques Rousseau. The phrase was revived and instantly picked up as they appeared on placards and vocal chants. The phrase has historically been associated with anarchist, socialist and other anti-capitalist movements.
In January 2021, the stocks of Gamestop, AMC Entertainment, Nokia, and a few other companies skyrocketed as part of a speculative trading frenzy. The stocks of Gamespot, at one point, went as high as $483 per share. This forced many trading companies like Robinhood to halt the purchase of new stocks by traders. Later, Robinhood backtracked from their initial decision and allowed limited stock buying to specific traders. Robinhood's move irked off many regular traders, and many of them took to the streets outside the NYSE building in New York City on January 29, 2021. Videos on social media showed dozens of protesters chanting slogans against Wall Street traders. Protesters can also be heard swearing at Robinhood for restricting them from trading on AMC and Gamestop.