Statements only make sense in context. 

We know the context, i.e. ongoing debate about the title Master, and the status of the people involved. 

One academic made a comment to some students, referring to the title of a second academic, i.e. "Master", and pointing out the incongruity of the students sharing the table, as equals, as Fellows, with this academic Master, and how that actual, current status had nothing to do with some long ago disappeared "slave master". 

Perfectly normal academic banter about academic politics. It would have been the same wording had the students not been black. But being black, they chose to take offence, and that is what changed everything. 

Which again points out the irony that those who were once oppressed are now the ones with the power, undergraduates making respected academics tremble.