No one has yet explained what was offensive or bigoted about the remark. 

It was an ironic comment about the appropriateness or not of the title "Master", when slavery was abolished 200 years ago and the oppressed group is now sitting as Fellows at the same table as the Master, in the context of ongoing discussions of said appropriateness, to Fellows he assumed were intellectual equals who would "get it".

Please explain what the unspoken assumption behind that thinking is. Is it that having once been oppressed is demeaning, so anything reminding people who belong to a group once demeaned that they were oppressed is insulting? ? No, that can't be it, since that is precisely what gives previously oppressed groups power today, referring to their past victimhood.

One minute we should be blind to race, the other being blind to race is offensive because it means ignoring oppression, etc. Do make up your minds.

So...what is the thinking behind finding offence in this remark?