Amazon is once again in Sen. Elizabeth Warren’s crosshairs, this time for its decision to cut medical benefits for part-time employees at Whole Foods, the company’s grocery chain.

Warren tweeted her criticism of Amazon CEO Jeff Bezos and said the move is the reason “we need #MedicareForAll.” Amazon did not respond to GeekWire’s request to comment by publication.

Jeff Bezos committed to providing his employees "important benefits"—right before Whole Foods cut health care benefits for hundreds of employees. This is exactly why we need #MedicareForAll. https://t.co/sa5MMD7wuf — Elizabeth Warren (@ewarren) September 14, 2019

On Friday, Amazon confirmed plans to cut medical benefits for Whole Foods employees who work fewer than 20 hours per week to Business Insider. The decision will affect about 2 percent of Whole Foods’ total workforce.

Warren tweeted a link to a separate Business Insider opinion piece accusing Bezos of hypocrisy because he committed to investing in employees a few weeks before cutting medical benefits for part-time Whole Foods workers.

Bezos was one of more than 100 CEOs to sign onto a pledge to redefine the “purpose of a corporation” to go beyond producing profits for shareholders. The commitment, initiated by the influential Business Roundtable, pledged to also take into account employees, customers, and other stakeholders.

In a subsequent tweet, Warren reiterated her commitment to breaking up large technology companies and adapting U.S. antitrust law to rein them in.

It’s also another reason why we need to #BreakUpBigTech. Amazon's anti-competitive merger with Whole Foods isn't just bad for consumers—it's bad for employees. https://t.co/xm19NnWn6Z — Elizabeth Warren (@ewarren) September 14, 2019

The proposal is part of Warren’s bid for the presidency in 2020. She’s emerged as one of tech’s toughest critics as she vies with other Democrats for the White House. But she isn’t alone. Fellow presidential hopeful Sen. Bernie Sanders has long criticized Amazon’s treatment of workers.

Last year, Sanders introduced the “STOP BEZOS Act,” which would have compelled Amazon to cover the costs of government programs that its lower-income workers receive. The bill never advanced but Amazon did change its policies.

A month later, Amazon raised its internal minimum wage for all employees to $15 per hour. The company also plans to spend $700 million on worker retraining programs to teach employees whose jobs could be automated skills in high-demand fields, like data science and business analysis.

Despite these changes, Amazon continued to earn the ire of Democrats in Washington D.C. On Friday, three U.S. Senators sent a letter to Bezos demanding answers on the network of third-party delivery contractors the company uses following critical reports of the program.