First off, this is just my theory.
There could be connivance of both Chinese and some of the Philippine Government officials.
The “higher ups” of Philippine government could be receiving bribe money from the Chinese government so that these structures can be built without any hindrance or problems.
The government buying of planes and boats supposedly to safeguard the territory is just one of the ways for some officials involved in the purchase to get a few millions for their own pockets.
Just a possibility.
Some of the wars that is happening around the world are just fabrication so that a few can make money out of it.