Japan protests as Chinese ships try to approach fishing boat near Senkakus

Is there any reason the Japan Coast Guard and Maritime SDF aren't more regularly patrolling their own waters?

They are disputed waters, not Japanese waters.

There is a simple solution to this.

Create a DMZ (demilitarized zone) to include those islands, and problem solved. That way neither China or Japan can enter those waters. Problem solved.

China causing trouble in the hood. Situation normal.

China Coast Guard was merely guarding Japanese coasts much as Japan ;protected China for many years. Why does China get yelled at for being benevolent and returning the favor to Japan. Senkaku has Chinese name, by the way, and is more Taiwan's than either Japan;s or China's.