The Webster’s Encyclopedic Unabridged Dictionary of the English Language (New York: Portland House, 1989), of which I have a copy, correctly defines what a Filipino is:
Fil·i·pi·no (fil’əˈpē’nō), n., pl. -nos, adj. —n. 1. a native of the Philippines, esp. a member of a Christianized native tribe. —adj. 2. Philippine. [< Sp. derived from (las Islas) Filipinas Philippine (islands)]
Take note of the phrase “a member of a Christianized native tribe”. This is historically precise because it was the Spanish friars who, upon baptizing the indigenous, automatically Hispanized them. We say automatically because the once pagan indigenous were assimilated into the societies (reducciones which later became pueblos, parroquias, etc.) that were created by the friars for them. In other words, those who were baptized or Christianized were welcomed into a new society which provided them the benefits of cultural dissemination, in a way “civilizing” them because new concepts and tools from the West were by far and comparatively more advanced vis-à-vis the latter’s cultural way of life.
From these baptized ethnolinguistic groups or tribes evolved the Filipino.
In this regard, it is scientifically, culturally, and historically imprecise to say that the Ifugáos, the Mañguianes, the Aetas, the T’bolis, even the Moros, and all the other unbaptized ethnolinguistic groups to be called Filipinos for the mere reason that they did not assimilate themselves into the societies that could have shaped and molded them into the Filipino cosmos that was the world of José Rizal, Marcelo H. del Pilar, Padre José Burgos, Luis Rodríguez Varela, and the rest.
This Webster definition is the reason why, in a previous blogpost (Filipino, in a jiffy), I named only three attributes which defined what a Filipino is:
1) Hispanic culture, with Malayo-Polynesian elements as a substrate.
2) The Spanish language.
3) Christianity (Roman Catholic Religion).
The indigenous who never got the chance to be baptized into the Christian faith were not Hispanized, thus failing to be Filipinized in the process. Of course, we can still say that the rest —particularly our indigenous brothers— are Filipinos. But only by virtue of citizenship (most notably, jus soli).