J.P.
Before you hop to gender discrimination, (which it seems sorta like the case), you should consult a labor union such as Teamsters or another or at best an attorney.
Florida is a right to work state, however, your saving grace may be they never eliminated any position and lied to you by saying so. (or so it sounds. They do need to offer considerationa although, I do not believe that is law).
It my personal opinion, they can not promote, then demote, the hire back on the old guy. They need reasons for doing so. I wouldn't pull out gender discrimination until someone else can verify, or substantiate the claim. I say this because YOU don't want to seem like the bad guy - let someone else do that for you.
I know it stinks, but perhaps you should find yourself a career that you know you can promote in and even though it seems like "they" win, you can still hold your battle doing something better.