I'm not a historian, but I grew up in Florida, and had to do a bit of research for classes.

Before WWII, there were less than two million people living in Florida (compared to ~20 million today). Before a/c was affordable, Florida wasn't the most pleasant place to live. I don't know about swampers in particular, but Florida and Floridians were definitely involved in the war. There were ~250k soldiers and ~300k volunteers for civilian defense activities from Florida.

Because of the plentiful flat land there were 172 military bases here by the end of the war, and the miles of coastline and the tropical climate made it the perfect training ground for beach landings.

After the war was over, a lot of soldiers ended up settling in Florida because of the climate, growing economy, etc., which contributed to the rapid growth in population over the next few decades.