Hacking hits water plant in Florida

Via the New York Times, this bad news: 

Hackers remotely accessed the water treatment plant of a small Florida city last week and briefly changed the levels of lye in the drinking water, in the kind of critical infrastructure intrusion that cybersecurity experts have long warned about.

The attack in Oldsmar, a city of 15,000 people in the Tampa Bay area, was caught before it could inflict harm, Sheriff Bob Gualtieri of Pinellas County said at a news conference on Monday. He said the level of sodium hydroxide — the main ingredient in drain cleaner — was changed from 100 parts per million to 11,100 parts per million, dangerous levels that could have badly sickened residents if it had reached their homes.

“This is dangerous stuff,” Mr. Gualtieri said, urging managers of critical infrastructure systems, particularly in the Tampa area, to review and tighten their computer systems. “It’s a bad act. It’s a bad actor. It’s not just a little chlorine, or a little fluoride — you’re basically talking about lye.”

So that's bad, i.e. someone is up to no good with the internet, and intends to do Americans harm. (Imagine if they had access to the potassium permanganate supplies!) Here's my question - why are we hooking up physical infrastructure to the internet? That seems unwise...