Elon Musk lashed out on Wednesday on Twitter—the social media platform he has perhaps pretended he will buy—to complain that Tesla has been dropped from a stock market index that includes companies committed to the environment, social concerns like diversity, and corporate governance.

“ESG is an outrageous scam!” Musk said, referring to the acronym that represents those factors. “It has been weaponized by phony social justice warriors,” he tweeted separately.

Musk followed up by posting a meme featuring Dwayne “The Rock” Johnson, with a caption that defined a company’s ESG score as “how compliant your business is with the leftist agenda.”

In a blog announcing this year’s updates to the list—known as the S&P 500 ESG Index—the business’ head of North American ESG Indices, Margaret Dorn, forecasted Musk’s professed outrage.

Elon Musk Lashes Out After Tesla Dropped From ‘Social Good’ S&P ESG Index