Former Dallas Mavericks majority owner Mark Cuban blasted Elon Musk in a lengthy rebuke on social media Wednesday after the billionaire Tesla owner described corporate diversity initiatives as “racism.”

Cuban took Musk to task in a statement posted to the executive’s social media platform X on Wednesday night, hailing support for diversity, equity and inclusion efforts at U.S. companies.

“Good businesses look where others don’t, to find the employees that will put your business in the best possible position to succeed,” Cuban said in the series of posts. “I take it as a given that there are people of various races, ethnicities, orientation, etc, that are regularly excluded from hiring consideration,” he said, adding, “By extending our hiring search to include them, we can find people that are more qualified.”

Cuban seemingly did his homework on the topic as he spelled out the advantages of DEI policies in five long takes after Musk condemned the practice in a statement to his platform.

“Discrimination on the basis of race, which DEI does, is literally the definition of racism,” Musk wrote Tuesday. 

In another post minutes earlier, Musk complained “DEI, because it discriminates on the basis of race, gender and many other factors, is not merely immoral, it is also illegal.”

After about an hour, Cuban weighed in, emphasizing the importance of diverse voices for businesses to serve a wide range of consumers from varying backgrounds. He criticized corporate executives who treated DEI priorities as a “checklist item” instead of a core principle, emphasizing the positive impact on employee productivity.

“When companies do DEI well, you see a well-run, successful company,” he said in the post.

Many corporations and institutions have worked to integrate DEI values into their operations over the last decade as brands shift their stance on recruiting to attract diverse talent.

Advocates say DEI is critical to creating an inclusive and respectful workplace environment for marginalized employees. However, critics contend that many companies are too fixated on numerical goals rather than addressing deeper issues. 

Before Musk was schooled on the subject by Cuban, the Tesla owner expressed support for the opinions of billionaire activist investor Bill Ackman, who posted a 4,000-word essay on Wednesday condemning DEI initiatives in light of the recent anti-Semitism controversy surrounding former Harvard President Claudine Gay, who has benefited from such policies.

The issue has become the latest culture war on the national political landscape, with conservative advocates continuing to urge colleges and universities to abandon initiatives that they assert promote diversity by disenfranchising white men.

In another tirade assailing DEI last month, Musk declared, “DEI must DIE,” while basically describing the initiatives as a form of reverse discrimination.

Last month, Musk also praised one of Ackman’s letters to Harvard calling for Gay to step down.

“Your letter simply articulated, with great clarity, the severe concerns held by many,” Musk said at the time, while Ackman also rushed to Musk’s defense in December when the X owner was accused of being anti-Semitic, calling him a “free speech absolutist” after reopening the platform to extremist viewpoints.

“To use a Muskism, Earth is fortunate that X is owned by an individual that is largely insulated from financial and other influence,” Ackman said on X.

“We all should be grateful that X is owned by Musk,” Ackman wrote.