Mad Men has always been uncomfortable about race - rather intentionally, one could presume, given that the show is all about keeping up appearances while everything falls apart.
The “white picket fence” imagery was hugely important for the show’s first few seasons, but now, as Mad Men’s characters have moved into the city (and into ugly apartments with weird recessed living rooms) so too have the stuffy edifices of the suburbs disappeared.
So while "The Flood," which takes place on the day Martin Luther King, Jr. was killed, echoes the season 3 episode "The Grown-Ups," which centered on the Kennedy Assassination, the subtext is entirely different.
Both Kennedy and King represented hope; both were profoundly eminent and meaningful figures from the 60’s.

