Mark hasn't taken back his comments about his users being "dumb fucks" for "trust[ing]" him, as far as I know, although he has apparently said that he regrets saying it[0].
[0] https://www.newyorker.com/magazine/2010/09/20/the-face-of-fa...
Source: research and I've asked FB myself
What's the difference between this and taking it back?
What's the difference between this and taking it back?