That is the title of a comic 1969 movie about frantic travel in Europe, trying to cover too much ground. I haven't seen it, but the term has been used on this newsboard before.
https://en.wikipedia.org/wiki/If_It%27s_Tuesday,_This_Must_Be_Belgium
It doesn't matter whether you add time in Florence, it depends on your interest in the history of Western art. I really meant it as a point that your itinerary is too oriented towards touching a list of bases, and not enough on seeing things that you "know" that you want to see. I see the selection of Geneva as an example of insufficient research about what you actually want to do. I've been in Amsterdam three times. If you consider commuter-rail easy-daytrips, Amsterdam alone is good for five to seven days. I spent three days in Baton Rouge and didn't see as much of the area as I wanted to! You didn't mention Spain, but my wife and I spent three weeks in Spain and didn't see it all. Italy probably has more to see and do than does Spain.
You stated a strong interest in the Rhine, but did not name an area of France that interests you. Did you mean eastern France, near Geneva? Did you mean you want to hit Paris again? Did you select Geneva solely on price, or is it particularly well served from New Orleans? Have you considered flying through Houston?
Another idea might be flying Amsterdam/Milan or Amsterdam/Venice:
Amsterdam 4
Cologne 2 (train)
Boppard 2 (train)
Strasbourg or Freiburg 2 (train)
Zurich or Lucerne 2 (train)
fly to Venice 3
Florence 3 (train)
Siena 2 (train or bus)
Milan 2 (train, Last Supper ... ) fly home
This itinerary is not meant to be definitive, it's just a better use of time than your original. It is difficult to exaggerate how hot and crowded Siena is in the summer. Milan is not the most interesting city in Italy, but it has lots of flights and is more interesting than Geneva. If you are desperate to see Munich, that could replace Strasbourg/Freiburg with air travel. But it's not the best city in Germany, that might be Berlin.