Owner of Facebook Mark Zuckerberg warns his racist Staff -'Stop crossing out #BlackLivesMatter for #AllLivesMatter

Some Facebook staff have been writing the term “Black Lives Matter” on the community chalkboards in Facebook's head office due to the outrage over the police related deaths of Alton Sterling and Philando Castile but some hateful persons have been coming behind them and crossing it out, replacing it with the term “All Lives Matter” instead.
Facebook C.E.O Mark Zuckerberg posted an 'angry' letter on his Facebook page, warning all members of his staff who do such to desist, as the #blackLivesMatter movement is an important American social issue that shouldn't be joked with.