I somewhat agree with your point, but I'd quibble with the analogy, and its implication about the usefulness/importance of fences.
I'd argue that the Internet is less like water, and more like a freeway. (It is the "information super-highway", after all!)
We do put (quite tall) fences up between freeways and residential areas (or between freeways and areas with wildlife!), and for good reason: unlike deep water (that both humans and animals have a vague instinct is an "unknown quantity" best to be approached cautiously), a freeway can, at a non-rush-hour time, look like a perfectly safe and quiet and predictable place — a place just like the calm, safe meadow or bike path or residential lane beside it — until, midway through crossing one, a truck sudenly whizzes over the horizon going 120mph and smashes right into you before the driver has time to react.
And that's the Internet: a seemingly safe, predictable place — with unexpected trucks whizzing through it, ready to smack into you.
Freeway is a great example in more ways: large swaths of society were destroyed in the process of making them (less purposefully in the case of the Internet/social media I think) and paradoxically reduced social connections despite seemingly making it easier to travel/connect. Now everywhere is unsafe because of car dependence/social media everywhere (i.e. Pauly Likens meeting adults on grindr https://www.newsweek.com/missing-teen-dead-pauly-likens-dash...)
Fair and I'll run with it. Where I live (Lisbon) it's very very easy to get to unprotected highways with no fences. No trouble at all, maybe a 15-minute walk from my home. No epidemic of kids being run over. We still fence them, where we want to pretend highways don't exist. Also a good analogy.
I'd argue that the Internet is less like water, and more like a freeway. (It is the "information super-highway", after all!)
We do put (quite tall) fences up between freeways and residential areas (or between freeways and areas with wildlife!), and for good reason: unlike deep water (that both humans and animals have a vague instinct is an "unknown quantity" best to be approached cautiously), a freeway can, at a non-rush-hour time, look like a perfectly safe and quiet and predictable place — a place just like the calm, safe meadow or bike path or residential lane beside it — until, midway through crossing one, a truck sudenly whizzes over the horizon going 120mph and smashes right into you before the driver has time to react.
And that's the Internet: a seemingly safe, predictable place — with unexpected trucks whizzing through it, ready to smack into you.