You'd have to shove awfully hard -- hard enough to crumple the metal shell of the USB connector, since it's wider than the opening in 120VAC socket. (I just tried it with a spare electrical outlet, and even with a fairly hard push and wiggling it around, I couldn't make it fit)

The long vertical slot you could come in contact with is neutral. The bottom peg is ground. The top right vertical strip is hot but it also has recessed connectors and is smaller than the usb c connector.

I'd be impressed if you could cause a short on purpose with significant force let alone fumbling in the dark.

The same issue would exist with any universal in-wall DC power supply -- if consumers buy a substandard product, it can destroy their device. Unless you want separate ports different voltage/power output then the user has to buy separate cables for each one.