I don't agree that it is confusing.
There have always been a few different connectors around the Hi-Fi world - not to mention just around the house generally - - 3 pin mains, 2 pin mains, Fig 8 mains, phono, din, 4mm ( banana) speaker, bare wire speaker, 2 pin din speaker, odd din variants ( B&O, Naim, Quad).
Plus a few others.
Trying to plug a phone charger into a mains socket (or whatever your student mate did) is just not being careful.
There are various mini-usb connections around - some carry voltage to charge phones, some don't. Even some connectors that look the same can be fully / partially wired ( scart, DVI, din ) leading to errors.
This has always been the case, in some form or other.
Anyone who wrongly plugs a power cable into a signal socket, or vice versa, is simply rushing without reading the labels/manuals first.
Please note, I am not being unsympathetic - I have done things like this myself - but the fact that something could be done wrong by a user is no reason for a manufacturer to not use a style of plug/socket - as long as they label it correctly.
If you put the wrong fuel in your car, is that the makers fault ? No, its yours.🙁