Like any of the USB A male to male cables that you can use to transfer files between to machines, or the USB A female to female adapters you can use with one of these cables to create an extension cable? If they’re banned, I wouldn’t expect them to be as widely sold.
The male to male cable to transfer between machines probably has a device with two slave ports in it. There's EE reasons, as well as protocol reasons why just plugging two hosts into each other is a bad idea (and fixing that was most of the work behind USB OTG).
Female to female is fine, because there shouldn't be a host with a male end that isn't OTG.
And beyond that, there totally exist the banned adapters (C female to A male) but that has more to do with the fact that you can get anything from China, regardless of trademark infringement.
You mean the A to A cables that warn that you may damage your computer if you connect two computers? Or the A to A “cables” that are actually a tiny device that relays data between two computers?
