Bollocks!
If we talk about historical claims Champa/Malay people would own the spratelys. Vietnamese were in the red river delta. The islands were occupied by austronesians long before you viets came around, therefore the Chinese have equal claim.
Your country is not so innocent my friend, china is giving you a taste of your own medicine. Lol. How about the cay island invasion?
"The sixth largest Spratly island. Only 1.75 miles (2.82*km) from Northeast Cay and can be seen before the horizon. Previously a breeding place for birds and covered with trees and guano. Export of guano was once carried out "on a considerable scale." Fringing reef partly above water at high tide. Vietnam erected its first lighthouse in the Spratlys here in October 1993 and built an airstrip. Has a three-story building, garrisoned by soldiers. Philippine military controlled the island before early 1970s. South Vietnamese forces (Republic of Vietnam) invaded the island in 1975, when Filipino soldiers guarding the island attended the birthday party of their commanding officer based in the nearby Northeast Cay. A confirmed report came out that Vietnamese prostitutes were sent by Vietnamese officials to the birthday party, supposedly a sign of good brotherhood between the forces, but was actually used to lure the Filipino soldiers guarding the island. Filipino forces apparently planned on attacking the island, thus it would have led to a war, but Vietnamese forces were able to erect a huge garrison in the island within few weeks, forcing Filipino officials to abort the plan. Since then, more soldiers were assigned to Parola Island (North East Cay), to avoid it from happening again. This was confirmed by interviews with soldiers involved in an episode of the defunct ABS-CBN's Magandang Gabi Bayan (Good Evening Nation) program. See Policies, activities and history of the Philippines in Spratly Islands#Southwest Cay invasion for more details. Part of North Danger Reef."
"We own more islands because it's ours." Lol... You can't fool them all. I say everybody get the hell out of scs and let the Chinese and Vietnamese duke it out.
Wiki cay invasion
Have a look at how many islands Vietnam occupies, greedy? Learn to share my friend. You can't take all for self. Lol
wiki/Spratly_Islands_dispute