Double clutch, what are you driving, a dump truck? Please tell me you didn't take that quote from TF&TF seriously.
I don't rev-match, I only downshift for two reasons... the first being I'm stopping slowly, engine braking. The second is I'm about to haul ass, rev matching not required... smack the throttle, pop the clutch, away you go.
If I'm putting around the neighbourhood I'll doubleclutch from second to first, just because it get's ride of the 'TWACK' sound... but that's all you can do on the bike, N is between 1 and 2 dude, that's it.
There are not really any situations where motorcylcists double clutch to my knowledge. I don't think I've I've done it once in twelve years of riding... unless you count missing a gear
Many many bikers do rev match, just like you heel/toe shift in a car. It is usually called throttle blipping and it serves basically the same purpose, although you are more concerned about stepping the rear end of a bike out going into a corner than a car. But it is about smoothness and keeping the chassis and suspension right where you want them.
Rev matching on a bike is not AS necessary to going fast as it is in a car tho and on most of your modern bikes you may not really need to worry about it at all. My bike came with a "slipper clutch" that will absorb the task for you, should you really slam it down without blipping.