If I rent a movie, my friends can watch it free of charge. If I buy a pizza, my friends can have a slice free of charge. If I purchase a CD and play it at a party I don't go around charging everyone that's listening to it. Also, you can only have 100 friends on your list so they would obviously sell more than 1 track pack.
What better way to encourage people to buy the tracks for themselves then by letting them have a taste of it's magnificence online? Just like the free samples at the grocery store, we'll give you a taste which will make you want to buy your own! The value of these tracks just went way down since I'll only be able to race on it with select friends who also bought the DLC. Why would I want to set the track to something that would eliminate some of my friends from being able to race with me? "Sorry guys, you're not allowed to participate in this race because we're going to do it on a track you don't have access to." Again, 👎
I understand your guys point, but for me it just made these DLC tracks almost worthless.