All the countries in the region have wildly overlapping claims.
Look at the timeline. Obama stood up in Parliament in 2011 and declared the "Pivot to Asia" and the new military base near Darwin and started the "Freedom of Navigation" naval exercises , all clearly directed against China.
Considering the US bombing and destruction and invasion of Iraq/Afghanistan that was ongoing at the time, China had no choice but to take defensive actions and prepare for the coming US onslaught. 90% of shipping thru the South China Sea is going to and from China, China needs to protect it.
I think what is ridiculous is that after WW1 an WW2 and the complete overwhelming dominance of the global economy the world is still divided into competing nation states. Ridiculous and the source of all "competing claims", trade war and war.
