Only one of these people's descending was so good that it won him two GTs in which he definitely wasn't the strongest climber in the race. Only one of these people routinely put minutes into all the other GC riders when everyone was going all out. And somehow, he isn't even winning the poll.
Also think the 'we never see the best descenders because they're in the grupetto' talk is severely overstated. Even in races where the heavier guys can do something on camera on the descents (from the break in a transitional stage, Sanremo when it was a sprinter's race, and so on), it's usually the familiar names nuking the descents.