I don't know why your surprised. As you said it was a Harley rally which means it's about show offs all wanting to be the coolest dog at the show. The big wheel definitely looks cool and if all your going to do is ride from Pub to Pub it's fine. Unfortunately, I doubt it helps in handling or riding quality.
Of course there were more bagger's there. It's called evolution. Most bikers eventually graduate from cool and realize they would really like to travel on their bikes. To do that, they have to pack an extra pair of underwear. The'll need storage space for that not to mention space for all the goodies they're going to buy at the rallies their traveling too.
It's evolution sort of like when they graduate from Harley to Honda.