My point is that they don't realise that by allowing an American attack from their territory they're risking their whole country. They have been led to believe that they can provide a safe harbour to American aggression without facing consequences. As long as they believe that they can safely behave in an aggressive way, they will not be deterred from doing so
For example, when American drone strikes in Libya or Syria use the Ramstein air base, then Germany itself becomes a legal target for retaliation. They just don't know it, because no recent victim of US aggression has had the ability to strike back at countries supporting aggression. According to the Hague conventions, neutral states even have to intern soldiers of belligerent states, so even if a country doesn't allow the use of its territory for aggression, simply hosting Americans could be argued to make an attack on them legal, if China chooses to do so.
We can't be sure that they actually don't know. Basic logic would tell anyone that attacking the world's no1 or no2 military that's right next to you is much different from attacking a nobody third world country that has barely any equipment. Of course, among some people, basic logic is in short supply, but that doesn't mean they're necessarily that stupid.
Leaving aside the logistics of whether Manila's leaders have basic logic or not, that doesn't change the fact that they would very likely be a pure liability to US' invasion plans.
Unlike Japan which actually brings forces to the table, Philippines has nothing. Even a couple of 054As and a landing dock slipping through could in theory decapitate important Philippines' installations. US would need to massively lengthen their front, which reduces the opportunity window of a breakthrough towards Taiwan.
To me, it sounds like the idea of involving the Philippines is a double edged sword at best, and a seppuku sword at worst.
Having them there doesn't massively help US' game plan (rapid sea/air victory and fait accompli through Taiwan landing before Chinese mobilization), but it can ruin US offensive both in terms of PR (if China counterattacks and makes huge gains/decapitation strikes on the Philippines) and on strategic level (Philippines would be an undefended rear line, unless US commits massive defense forces there, which dilutes their offensive capable forces).
