Client isolation is very common on wireless and wired LANs these days in enterprise and guest network environments. You also have tools like dynamic arp inspection to block poisoning attempts via the network switch.

If you get past all of that, you still need a victim who is actively using a cli tool on macOS using https.

It’s not impossible, but the conditions are much more specific than those needed to inject porn into a webpage on a poorly configured school network in 2006.