I went to Dade and Broward county schools circa 1968-70 and they were very Southern and conservative.
Dade, Broward and Palm Beach are the most Lib Dem in the state and haven’t been remotely southern in decades. When I lived in Palm Beach County 1991-1994 we all knew that the “south” started somewhere north of Orlando (although you still had some fading red neck trailer communities near West Palm).