Apple’s Tim Cook and Facebook’s Mark Zuckerberg have an established history of taking shots at the other’s multi-billion-dollar enterprises. But in recent weeks, with Facebook embroiled in yet another scandal, Cook has upped the ante. Even before a contractor for data-analytics firm Cambridge Analytica was found to have leeched data from millions of Facebook users through an app, Cook was floating “well-crafted regulation” for companies like Facebook, adding that “the ability of anyone to know what you’ve been browsing about for years . . . and every intimate detail of your life—from my own point of view, it shouldn’t exist.” And after the Cambridge Analytica fiasco, his remarks became even more pointed: “The truth is, we could make a ton of money if we monetized our customer—if our customer was our product,” he told Recode’s Kara Swisher and MSNBC’s Chris Hayes last week. “We’ve elected not to do that.”

Cook’s criticism apparently did not escape the notice of Zuckerberg, who fired back on Ezra Klein’s podcast Monday. “You know, I find that argument, that if you’re not paying that somehow we can’t care about you, to be extremely glib. And not at all aligned with the truth,” he said. “The reality here is that if you want to build a service that helps connect everyone in the world, then there are a lot of people who can’t afford to pay. And therefore, as with a lot of media, having an advertising-supported model is the only rational model that can support building this service to reach people . . . I don’t think at all that means that we don’t care about people.”

He went on: “To the contrary, I think it’s important that we don’t all get Stockholm syndrome, and let the companies that work hard to charge you more convince you that they actually care more about you. Because that sounds ridiculous to me.”

To some extent, Cook and Zuckerberg represent where the ethos of Silicon Valley diverges: both offer life-altering products that profess to change the world for the better, but where Cook is up front about the cost, Zuckerberg’s business model is decidedly less consumer-facing. They’ve butted heads over this fundamental difference before, with Zuckerberg telling Time magazine in December 2014, “A frustration I have is that a lot of people increasingly seem to equate an advertising business model with somehow being out of alignment with your customers. I think it’s the most ridiculous concept. What, you think because you’re paying Apple that you’re somehow in alignment with them? If you were in alignment with them, then they’d make their products a lot cheaper!” In a speech months later, Cook seemingly addressed Zuckerberg’s “frustration,” saying, “I’m speaking to you from Silicon Valley, where some of the most prominent and successful companies have built their businesses by lulling their customers into complacency about their personal information. They are gobbling up everything they can learn about you and trying to monetize it . . . We think that’s wrong and it’s not the kind of company that Apple wants to be, so we don’t want your data. We don’t think you should ever have to trade it for a service that you think is free, but actually comes at a very high cost.”

In this most recent iteration of their feud, Zuckerberg makes a fair point: corporations don’t necessarily care more about the people who use their product because they’re charging them for it, as opposed to siphoning their data and selling it to advertisers. Amazon, for instance, isn’t necessarily a more ethical company just because it charges you $99 a year to be a Prime member, instead of giving you access to services for free and handing advertisers a file of information about ads you’re more likely to click on. But, as Bloomberg’s Shira Ovide points out, Apple’s operating profit margin is 27 percent while Facebook’s is 50 percent, meaning that Facebook is making a not-insubstantial amount of money from advertisers—its paying customers.

For the past year, Facebook has weathered continuous scandal over things like the spread of fake news on its platform, and its moderation of speech. And though both problems at their root have to do with the company’s core business model, Facebook has brushed off the question of a deeper recalibration by offering surface-level fixes. Now that Facebook is under fire for its handling of user data, however, questions are finally beginning to arise as to whether that model is ethical, and whether it can be allowed to continue unchecked. And as the threat of regulation looms, Cook’s remarks can be interpreted as an attempt to put as much daylight as possible between Apple and Facebook.