USB-C somehow managed to be the worst "standard." Hopefully the next big USB port doesn't allow for so much variance. I don't see why a specific wattage and data transfer rate isn't included in the specification. I can scarcely believe they managed to standardize it so well that I can plug the wrong cord into a port and break something.

Usually if a thing is not allowed, there is a good reason for it. Unfortunately many people seem to ignore that because they don't know or understand the reason.

How does this apply to a usb-c-to-headphone-port adapter, if at all? If someone's using one to regain access to a 3.5mm audio jack, are any risks posed?

If you want a more detailed explanation, USB-C is a small connector that was designed primarily for data transfer, extended power range delivery (240w) was essentially hacked on to the standard. Electricity arcing between the contacts on the connector is the biggest challenge with this hack, since the contacts are small and very close together, which could burn out the circuit board and start fires. For EPR to work safely, there needs to be a lot of extra components on the circuit board/female connector side, which there simply isn't enough space for on an f2m extension cable.

As for why USB-C cables are so short, it's simply a matter of physics, carrying high speed data over larger distances would result in higher losses and requires thicker conductors and more shielding, which is why you don't see USB4 Gen3 cables over 1 meter unless they are optical, and longer "charging cables" are only rated at USB 2.0 speeds, because more often than not they don't even have the USB 3.x data pins on their connector.

Anybody care to sum this up for people who can’t watch videos?

I'll have you know that I've been using a 2m extension on my deck power supply for a while and haven't had any fires to speak of. Almost none actually.

Technically extension cables were not part of the original USB spec, either, but that did not prevent oodles of them from appearing pretty much instantly. They solved a problem, there was a need, and thus they happened.

I.e. there never was supposed to be any such thing as a passive male USB-A to female USB-A cable, and yet pretty much every little MP3 player from 2001 to about 2005 came with one regardless.