I think what drag means is that the MP3 algorithm is safe to use as long as you don't use it in a device that compresses or decompresses digital audio samples.
So doing the computations mentally or on paper is okay, doing it in any device is supposedly covered by the patents. Which is totally absurd, of course, but unfortunately it is how patent law is interpreted currently.
Personally, I think a general computation device that can be programmed by its user to do many different things should not be covered by such patents, as the computer is only used there as a help to do the computations faster. (And of course "general" means that you can run on it whatever you want, not a locked down & restricted system... ;) )