As of Friday at 1 p.m. EST, both the SpaceX and Tesla Facebooks were unreachable.
"I'll just refer you to Elon's tweets this morning," a Tesla spokesperson said in an email to CNBC Make It.
SpaceX declined to comment.
Then Musk went on to respond to WhatsApp co-founder Brian Acton's tweet asking users to delete Facebook, a call to action that has been circulating in the wake of the turmoil of the Cambridge Analytica data scandal.
Another user responded to the chain, suggesting Facebook was a "place for dumb people who believes Mark [Zuckerberg] and submit their personal data so that it can be harvested."
Musk responded with a seemingly sarcastic affirmation.
Musk went on to say he did not know there was a SpaceX Facebook page and would delete it.
When another Twitter user expressed disbelief, Musk doubled down.
Another Twitter user asked Musk whether he thought the Tesla Facebook page should be deleted, too. And again, Musk responded in the affirmative.
Musk says he has never used Facebook. He is, however, fairly active on Instagram and didn't indicate any problem with the photo-first social media platform. (Facebook acquired Instagram in 2012.)
Instagram's probably ok imo, so long as it stays fairly independent. I don't use FB & never have, so don't think I'm some kind of martyr or my companies are taking a huge blow. Also, we don't advertise or pay for endorsements, so … don't care.
Though Tesla and SpaceX, prior to Friday, maintained Facebook pages, the companies did not pay to advertise on the social media giant, says Musk.
We've never advertised with FB. None of my companies buy advertising or pay famous people to fake endorse. Product lives or dies on its own merits.
An email to Facebook had not been returned by the time this story was published.
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This story has been updated and revised.