Sure, but you aren't going to get a quality rip that way. Pointing a camera at the screen is going to produce incredibly shitty results even compared to DVD. Do you really want to invite your friends round for a movie night and then show them a camcorded super compressed rip? It might be OK for personal use if you don't care about quality at all, but then a camcorded copy from a cinema will work just as well.
He's talking about grabbing the uncompressed digital signal, for example having a screen-capture program running on your computer when you start a movie. It's not as ideal as grabbing the original compressed signal, in a decrypted form, but it still works. For a typical DVD, for instance, instead of taking the original MPEG-2 signal and decrypting the CSS, you could dump the movie into an uncompressed video. Assuming 24-bit color, that would make a 160GB video for a 90-minute video in NTSC.