Why did the filipino insurrection against the united states take the form of guerrilla warfare rather than all-out war?

The correct answer is:

Filipino rebels did not have enough weapons to fight American troops in all-out war.

The Philippine-American War had two phases. The first one (February to November of 1899) saw Aguinaldo, the Philippine leader, attempting unsuccessfully to fight an all-out war against the better equipped American troops. The lack of equipment pushed the second phase of the Filipinos strategy. They shifted to guerrilla-style warfare from November of 1899 until the spring of 1902.

It was a last resource adopted by the Filipinos to fight aganst the United States.

Explanation:

At the beginning of the Philippine-American War, the Filipinos fought an all-out war with the United States, however it was not successful and changed the tactic to fight as guerrilla. They saw how skirmishes were more effective to fight against the Americans. The Philippine Army began staging bloody ambushes and raids with good results for their side as the victories at Paye, Catubig, Balangiga and others.