The Chinese perspective is simple. Their view is that the South China Sea is an integral part of Chinese territory from time immemorial and everyone else is trespassing.
There is no such thing as other claimants, because there is no claim. The South China Sea is as much part of China as Beijing is part of China. Mind you, the South China Sea is not Chinese EEZ. It is China's "blue" homeland. Their internal rhetoric is very consistent on this and is accepted without question by the Chinese (if any Chinese academics disagree, they know better than to say it).
Given this baseline, any action that is not silent acquiescence can easily be spun as provocative and aggressive. What matters is not the actual action, but whether the Party sees the corresponding nation as a friend or not.
For example, some three years ago I saw a series of TV programs covering the South China Seas. As part of the show a Chinese Marine Surveillance ship was shown proudly and bravely rescuing Chinese fishermen from a "foreign warship". The problem is that the coordinates shown corresponds to the Indonesian EEZ. This is not the CCTV mistakenly putting the wrong numbers, because the coordinates were shown on the CMS ship's navigation screen. The foreign warship has had its flag blurred out, but from the silhouette someone said it was an Indonesian navy ship.
A warship threatening your fishermen is normally a big deal. The Indonesian Navy ship was probably going to arrest the Chinese fishermen for poaching, but if China says the SCS is their integral territory (listen to what the Chinese officers say, their warnings consistently say "Chinese territory", unlike the Chinese diplomats who still keep things vague), then it would have been a foreign military entering sovereign territory to kidnap one's citizens. This ought to be a big diplomatic mess. But nope, barely anyone ever heard about it. I don't claim to know why, but I speculate that it is because China sees Indonesia as a friendly nation.
Contrast that to the Philippines taking the issue to UN arbitration. No warship involved. No lives involved. It doesn't seek to establish who owns the area, merely to establish that the islands in question are rocks that can not naturally sustain people and thus can't generate EEZ. This does not even conflict with China's own claim, since China does not base the Nine Dash Lines on the rocks but rather states that the Nine Dash Line is Chinese territory, period. No justification given because none is needed. And yet the filing of the arbitration is considered highly provocative.
While hypothetically some action is obviously aggressive and provocative (e.g., actual shooting), it's impossible to determine what action is unquestionably non-provocative and non-aggressive because China can always choose to view it as provocative.
I share the hope that diplomacy will provide a solution. I watch Chinese TV from time to time and it is a useful barometer. But as long as their internal propaganda says that it is their homeland, though, then diplomacy can only delay things, not solve it. When their media starts saying that the SCS is Chinese EEZ, then maybe we can hope for a real solution. Because EEZ can be negotiated, but homeland is not.
