Because since Florida has had longer and more immigration from the North, the demographers have differentiated it from the other states of the former Confederacy. Add to that the significant Cuban, Caribbean and South American populations on its SE (Miami) coast add to that differentiation (for now.)
One of the markers of that status is that it was the first post-reconstruction southern state to elect a Republican Governor, Claude Kirk, in 1967 (I believe).
“Why do all these reports omit Sen. Bill Nelson (D-FL)?”
Nelson was beatable in 2012. However the establishment decided to run a legacy, Connie Mach IV, instead of a strong candidate.
North and parts of Central Florida are very much like South Georgia...the Deep South.