The date of transmission. Politically it made the Okinawans look "better" to the Japanese if they could claim that the Chinese influence on their arts occurred several hundred or more years in the past, rather then continuing through the 1800s. In the late 1800s Japan fought a war with the Chinese, seizing present day Taiwan. The Japanese also looked down upon the Chinese because of the weakness of their central government, and how European powers were seizing territory from the Manchu dynasty. For example the Shanghai concession.
Sorry for the necro.
This is pretty well established these days as well.
For instance :
Kanryo Higashionna (1840 - 1910) the "Fist of Naha", is known as the man behind the Goju-ryu karate style. Higashionna began his training in Okinawa it was actually in China that the true seeds of Goju-ryu were planted. Higashionna went to China and studied under a man named Master Woo (Ru in Japanese) who was a practitioner of Chinese boxing. Higashionna trained under Master Woo for aproximately 15 to 20 years.
On his return to Okinawa he combined his native fighting system with the Chinese system and became the father of Naha-Te (Fist of Naha). It did not take long before his fame spread throughout the island and students started to come to him for tuition. Among them was a student named Chogun Miyagi.