Why? historically the Japanese did attack Pearl, the Philippines and South-East-Asia more or less simultaneously.
Bringing in their Naval assets (free from engaging Pearl and the Philippines) towards South-East-Asia would have contributed even more to their already Blitzkrieg like actions - or
this part of the IJN and Japans Taiwan based Air-force would have been set aside as a "guarantor" for keeping their Pacific flank protected in case the USA would have decided to disagree with Japans war-plans.
What I'm saying is if the fleet is already on the way to Pearl and the Americans suddenly are obviously aware they are coming then they can't just divert the Hawaiian raid to the south. They are either going to need to go ahead and attack anyway or return to a safe area to regroup.