These demands go well into the territorial waters of numerous countries, just north of the Philippines, Indonesia, Vietnam, and Malaysia. They not only do this for civil aircraft, they also redirect civil shipping in established shipping lanes.
Hear this on the radio going on around Taiwan, Korea and Japan as well.
It is bullying, Indonesia sent out 4xF16s and some Naval ships, then the Chinese government came back to the negotiating table, claiming historical fishing rights within the Indonesian EEC. Chinese Navy blatantly undertook seafloor mapping in Indonesian waters, this was done with submersible drones and ships. They were repeatedly were warned off by Indonesia, they persisted. As a result of this mapping, they send subs through Indonesian waters without permission.
The purpose is to establish control thus create evidence for territorial claims, the encounters seen by the shipping traffic are Chinese “Coast Guard” passing themselves off as PLA Navy. The place themself stationary within the shipping lane in way of the established path to make ships alter course.
It is downright dangerous, they raped and pillaged the reefs, totally destroyed some to crush up to make artificial island. They use cyanide fishing techniques, and prevent countries in the area from conducting legitimate resource gathering within their own EEC.
The Philippines already took the B/S “9 Dashed Line” case to The Hague, and won, China ignores the ruling and demands to control the air, land, and sea through intimidation.
Personally I see these activities as unlawful interference of internationally agreed practices.