I have nothing against instructors using the name of a military unit to sell either their own hand-to-hand combat system or one that is used effectively by that unit. Not at all. For the most part, I see this as a marketing thing and each instructor/author has to make decisions on that front.
If you want to connect a USB device to an HDMI device then you must use a converter box. This is a set of electronics that change the protocols and signals. The only adaptor which works is the DVI-HDMI ones.
But, if you use a cable box, the cables from the cable box to the TV sends an analog signal to the TV. Your TV has to reconvert it back to HD which loses some quality. The HDMI cable sends the HD signal directly to TV.