It's Apple's fault if people use knock-off chargers? (And you can't even argue that Apple wants that...)

Arguably. Selling an unusable device, that is turned into a fire hazard when you type "Iphone charger" into google, amazon, or alibaba in an attempt to get a fully working device has blame to go around but I would not say Apple is blameless. The most damning is really that Apple is the only individual here with an easy and cheap alternative, just sell fully usable devices.

Is the appliance maker responsible for faulty wall sockets? Is the wall socket maker responsible for faulty wiring? Is the toy maker responsible for faulty batteries? The automaker for faulty oil?

This makes no sense. The government should fix their charger regs and prosecute companies who don't comply, if the chargers are causing electrical fires.

No reasonable person expects an iphone to come with a building or breaker, and many are bought by the homeless. An iphone charger is part of a functioning ipohne, a wall socket is not part of any appliance.

The government has little control over what random Chinese devices you order. Countries cannot even prevent people from just mailing cocaine, imagine if every random Chinese electrical device needed to be verified to have been engineered to a certain standard. No counry on earth had 1/100th the border agents necessary to do that.