Keith, very kindly but I think you're missing some of the points? I don't think anyone is necessarily demonizing tourists themselves but an industry which has overloaded a place not designed for the numbers it is having to accommodate, and authorities who are digging in their heels where putting some reasonable controls on those numbers is concerned.
Aside from too many bodies, the affordable, available housing issue in Venice of particular concern. From a 2015 article:
"...over the past two decades, property owners have increasingly converted apartments into hotels or Airbnb rentals, driving up the costs of permanent housing. The result: only the wealthy can afford to live here."
"Longtime residents are being driven out by housing owners – who can make more money from wealthy foreigners buying swanky vacation apartments than they can renting to families – and by day-trippers, who don't spend enough money for the city government to acquire the kind of taxes it needs to set aside affordable housing for locals."
Lose the locals and you risk losing the culture.