The SCS was named after it had been used by the people in China for many years. During the 1940s, China government reclaimed the SCS as a part of China soil within the 11 dash line with the help of the US government that lent its navy ships to the China navy completing the survey and claim. Nobody rejected the claim of China government at that time. Therefore, the sea within the dash 11 line is the territory of China without doubt. Currently, China has right to protect her territory, but China has never oppose the freedom of navigation in the SCS given it is not harmful to the right and interest of China. It is absolutely correct for China and the nations surrounding the SCS to keep it peaceful and prospective because it is one of the busiest commercial seaway in the world.
We should ask why somebody is so upset with the righteous activities of China by sending their navy fleets to the soil of China. This is a big concern to all peace-loving nations around the SCS, as the presence of military powers from outside of the region would cause potential conflicts. Nobody would like to see a confrontation happen in the SCS, although the risk is rising. Of course, there are disputes on the sovereignty of the SCS between the neighboring nations including Philippine, Vietnam, Malaysia, Indonesia, Brunei and China, which all claim their respective 12 nm sovereignty and 200 nm economic zones. Such claims obviously overlap each other, but have all postdated the claim by China. Therefore, those claims are invalid! Those reefs occupied by these countries should be returned to China without a delay, although they also have right to negotiate with China regarding how to keep the peace of the SCS without intervention by other powers from outside of the regions, e.g., the USA.
Some think the Taiwan problem is also a part of the SCS issue, but in fact it is not. The problem cross the Taiwan straight is continuation of the civil war in China since 1949 when the Mainland was taken over by the China Communist Party, and the China National Party retreated to Taiwan. Both the parties' governments claim that it represents China, i.e. the People's Republic of China (in Mainland), the Republic of China (in Taiwan). This is a sad situation to all people in China including the Mainland and Taiwan. However, we should be optimistic for the future of people in China, and we should believe that the Mainland and Taiwan shall be reunified in the near future. This is a tendency of history. Nobody is able to block such a trend. Those seeking separation of Taiwan from the Mainland shall be punished by the history and be condemned by all people in China and the world as well.
If the Taiwan problem is resolved, the SCS issue shall not be a problem at all! Before this problem is solved, people in China are suffering from various aspects, such as that some countries have taken a big advantage of the Taiwan issue to get tons of benefits (or money) either from Taiwan, or from the Mainland. How can people in China bear of this situation continuing again and again? Are people in China so stupid or lacking of wisdom? I do not think so.
Look at the German people, and now at the Korean people that they have been reunified or start the process of unification. These are great examples that people in China should have learned from!