It does not matter the least what China considers their waters, this is international waters.

The sanctions were voted for by China as a permanent member of the UNSC, if China did not vote for it, there would be no sanctions.

In fact, the Australian crew whose lives China endangered along with their own pilot is enforcing the sanctions that China levied on NK by proxy.

Maybe China should stay in their own fucking waters if they can’t behave like people. Aviation is not a toy for dictators for international dick measuring contests.