The disagreement began when Malik, 22, retweeted a post by a Twitter user, @FemaleTexts, suggesting that Swift was being greedy by not releasing her music on streaming services, despite her financial success.
The post compared Swift's stance against music streaming services like Spotify to the more relaxed attitude taken by another successful young popstar, Miley Cyrus.
"[People] can still listen to my music if they get it on iTunes," the post read, quoting from a November interview Swift gave to Time magazine. "I'm always up for trying something. And I tried it and I didn't like the way it felt. I think there should be an inherent value placed on art."
The post compared Swift's view to the one provided by Cyrus in an interview with W magazine in February 2014.
"You know, I've made my money. If no one buys my album, cool," she said. "It's fine. I've got a house, and I've got dogs that I love. I don't need anything else."
The tweet described the difference between the two viewpoints as "astounding".
After seeing Malik had retweeted the post, Harris, 31, stepped up to defend Swift.
"You've made your money?" He tweeted at Malik. "Cool ... f--- the 99% of musicians who depend on these services to survive right? Yeah f--- em."
Harris sent a series of tweets to Malik, accusing him of being out of touch with everyday musicians.