It's not that the oil is "worn out", it's that you want to get the metallic particles out of the engine. During break in miles all the minor interference areas get worn in and it's common for that first oil change to have crud in it. Usually stuff you don't want to stay in the motor for long and contaminate the bearings.
I like doing a 'moto-man' style break in on my new bikes. Then change the oil at 30-50 miles and follow the recommended service intervals after that. Cheap insurance!! The 50 & 500 oil changes are to ensure you get those particles out of the engine. After that, normal intervals. And yeah, do change the filter too! :lol: