Why are Americans so confused about this?
The passage walk, is a ritual and a formal one to the Italians.
Americans can't just flood the walks thinking that they are witnessing anything. That is not what the Passeggiata is.
You have to dress up in your best, and you have to greet people and be a part of it. The Passeggiata is about showing off how good life has been to you.
This may be entirely lost in Rome and its walks. There are too many people that didn't understand the tradition, so they cattle though the old paths, expecting to see something where people stopped following the tradition because everyone else stopped following the tradition.
Dress well, and walk slowly, show off your wife. Its important to do so.