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.
A USB hub can help connect USB devices to computers with different types of connectors. USB 3.0, with its SuperSpeed connection, is shaped differently than previous ports. Memory card readers connect to a computer via USB. MP3 players often use USB cords to connect to a computer.