We get the same thing here, with the "riders clubs" who like to go "touring" together. They stagger themselves into a long line and ride at the pace of the slowest rider or bike. So they can be like, a dozen bikes strung out over a hundred yards long and moving at 1/2 the speed limit :-/
They tend to get really REALLY annoyed when I play Frogger with their dumb asses and slot into the gaps.
All kinds of bikes in the rider clubs... but I gotta agree, it's the Harley riders who think that cos they spent 10x as much on their chrome plated turds as you did on your bike, they bought the rights to hog the road.