In the wake of a terrorist attack in London earlier this month, a US congressman wrote a Facebook post in which he called for the slaughter of “radicalized” Muslims. “Hunt them, identify them, and kill them,” declared US Rep. Clay Higgins, a Louisiana Republican. “Kill them all. For the sake of all that is good and righteous. Kill them all.”Higgins’ plea for violent revenge went untouched by Facebook workers who scour the social network deleting offensive speech.But a May posting on Facebook by Boston poet and Black Lives Matter activist Didi Delgado drew a different response.”All white people are racist. Start from this reference point, or you’ve already failed,” Delgado wrote. The post was removed, and her Facebook account was disabled for seven days.