SpaceX and Tesla had more than 5 million followers, according to Venture Beat.
The company appears to be more active on Twitter, which is also evidently Elon Musk's social media network of choice. Accounts for both firms stay energetic on Instagram, which is had by Facebook.
Yet the question remains as to why Facebook has been allowed to police its own data-handling policies for almost 15 years.
Musk's official Facebook accounts no longer exists as of Friday.
Zuckerberg admitted this week that the company knew in 2015 that research firm Cambridge Analytica improperly obtained the private data of an estimated 50 million Facebook users. The satellite was being used by Facebook as part of the company's plan to bring Internet to parts of Africa. Developed in 2014, the software was created to compile information from people based on their likes on Facebook.
Musk has also questioned Zuckerberg's authority on artificial intelligence quite publicly.
Another user pointed Musk to Tesla's Facebook page and dared him to delete that too. "Will do", Musk replied.
But Musk has long had a touchy relationship with Facebook's chief executive, Mark Zuckerberg. And that might be one of the downsides of deleting your official Facebook presence: Unofficial and fake pages can spring up pretty quickly. Will be gone soon. The page of SpaceX and Tesla are now inactive and each of them has around 2.6 million followers.
In response, Musk tweeted: "His understanding of the subject is limited".
He said he would continue to use Facebook-owned Instagram for the time being, but lamented "FB influence is slowly creeping in".
Lewis Hamilton's big swipe at F1 and media
Hamilton was quick to dismiss suggestions that he may have reached his peak as a driver: "I hope not". I think it's very different times to when Fangio achieved it, compared to today.