The photo above shows shoppers blithely wading through the water while getting their groceries. On some discussion threads, concern is raised re what risk there is of electric cables/plugs etc contacting the water; others say that flood-prone cities have building codes that adjust for that (and that residents tend to wear rubber boots...)
Another consideration: I've not been to Venice, but my understanding is that when it floods, there are things floating in the water that one would not like to encounter, especially in a grocery store... One Redditor did opine that in situations like that shown above, the "5-second rule" re dropped food would not apply.
But on a more serious note, many writers are blaming this flood on global warming, melting glaciers, and all that. That's a naive (or intentionally misleading) viewpoint. Here's some relevant info from MIT from years ago:
The increased flooding is caused by two things: the city is sinking and sea level is rising.
After World War II, water needed by new industry was obtained by pumping groundwater from nearby areas. As the water table decreased, the islands began sinking. The practice of pumping groundwater was stopped shortly after the devastating flood of 1966, and the city is now sinking at the much lower rate of 0.4mm per year.
At the same time, the Adriatic Sea and other ocean waters have been rising at the rate of 1.6mm per year, perhaps due to natural causes. "It could be the ubiquitous sea level rise that occurs around the world and has been going on fairly consistently since the last glacial period," said Bras. "You can debate whether it is accelerating or not, but so far I see no evidence of acceleration."
The end result of this rising and sinking is that Venice floods when high astronomical tides - the tides induced by the moon - combine with high meteorological tides - the surge caused by stormy weather (low atmospheric pressure combined with winds).
Many people don't understand that land rises and falls (and therefore sea or lake levels fall or rise) around the globe for various reasons. Where we live in the Upper Midwest, the land is still rising in response to the disappearane of the glaciers many millenia ago. Their weight pushed the land down, and it is now rebounding upward. Consequently the shoreline of Lake Michigan is not the same as it was in the past, and some rivers flow in the opposite direction for their direction in geologic history.
People love simple answers, but the world is complicated.