Zuckerberg tells workers not to cross out "Black Lives Matter"

Mark Zuckerberg is reprimanding employees for not heeding his earlier warning to stop crossing out the phrase "Black Lives Matter" on a so-called free expression wall at the company's Silicon Valley headquarter and replacing it with with "All Lives Matter."

"There are specific issues affecting the black community in the United States, coming from a history of oppression and racism. 'Black lives matter' doesn't mean other lives don't -- it's simply asking that the black community also achieves the justice they deserve," the Facebook (FB) chief CEO wrote Thursday in a memo published by Gizmodo.

Zuckerberg said Facebook was investigating recent incidents involving writings on the walls at Facebook's Menlo Park, Calif., hub, saying he was disappointed by earlier incidents. The billionaire entrepreneur also said he had previously made clear the incidents were unacceptable and viewed their continuation as "malicious."

Zuckerberg noted that Facebook had never curtailed what people could write on the walls, but that the company expected everyone to treat others with respect, and "crossing out something means silencing speech, or that one person's speech is more important than another's."

Facebook has in recent years invested in a creating a more diverse workforce, which is 2 percent black.

The company did not immediately return a request for comment.