It was warned that cables that have been manufactured without following HDMI standards and guidelines might not provide a good or consistent signals and might be poorly made. They might also have the potential to cause electrical fires.
So the cables are working and are not really "fake", but more like counterfeit. It's just that they didn't pay for the stupid license, ~~just like USB-C,~~ and thus those cables are IlLeGaL.
Poor quality cables can be official too, as paying for the license may take money away from quality. The concerns can be understandable but it sounds more like FUD to make sure people keep buying the "official" and "legal' cables.
All in all it's just a question of laws and money for a stupid connector.
EDIT: See replies to my comment. USB-C is not licensed. It just costs more than micro.