Todd Spangler NY Digital EditorFacebook CEO Mark Zuckerberg conceded in a town-hall meeting with employees this week that the social giant fell down on the job in failing to remove a militia group’s “call to arms” that had urged followers to engage in violence amid the unrest in Kenosha, Wisc., following the shooting of a Black man.“It was largely an operational mistake,” Zuckerberg said regarding Facebook’s inaction on removing the “Kenosha Guard” group on the platform, even after multiple