Many cruises begin, end, or round-trip out of the Ft. Lauderdale/Miami cruise ports, as these ports are handy to the Caribbean islands, and to the Panama Canal transit. They are also logical jumping-off or ending points for trans-Atlantic repositioning cruises. Many retirees live nearby in Florida and both enjoy and have the time and $$ for cruising.
Those are the upsides to cruises which begin or end in Florida. The downside of such cruises is the concentration of former New Yorkers (and New Jerseyites) who now live in this part of Florida and who are likely to constitute a substantial fraction of your fellow passengers.
While it is politically incorrect to generalize about people from one or another part of the U.S., it is also true that such characterizations often are somewhat accurate. In my experience, many present and former residents of NYC and north Jersey are some of our least pleasant shipmates - loud, rude, aggressive, and sour of disposition.
Such people give the lie to the song lyric which says of NYC: "If you can make it here, you'll make it anywhere." Instead, the very characteristics which facilitate survival in The Big Apple seem likely to engender shunning in other, less hostile parts of the country. Being shunned isn't making it, in my estimation.
