Nobody is concerned "solely" with anything. There's a hierarchy of concern, and the hierarchy is different among different individuals. As stated above, the actual proposed expenditures for defence are not large, and there's still considerable debate over where the money is to be sourced. There are many other concerns, many of them equally pressing, some of them more pressing.
Don't expect ASEAN to close ranks, except perhaps with a statement. Not likely to happen. The level of perceived threat is very different for different members: the Philippines and Vietnam ar emore concerned, Malaysia and Indonesia less so, Thailand and Singapore still less.
You persist in casting this as all or nothing, "#1 threat" or no threat at all, as if there were no middle ground. As I said above, I never said the Moros were the #1 threat, I said they were the primary focus of US/Philippine military cooperation. The Philippine government has long classified the NPA as a greater security threat than the Moros.
The media make a brouhaha when there's an incident. When there's an incident in the south, the brouhaha and the US concern are all about the Moros. When there's an incident on Scarborough shoal, the media all look at that. The media are fickle, and if you look at coverage in any particular moment without the historical and political context, you're likely to get a quite inaccurate impression.
Nobody's looking at a threat of being "enslaved". The threat is of losing access to some fishing areas and to potential energy deposits. While being pushed around is humiliating and arouses an emotional response, most people here have much more immediate concerns.
It's worked in the past. Ferdinand Marcos cast himself as the sole bulwark against impending Commie takeover (despite being the best thing that ever happened to the Communists), and the Americans obediently threw vast sums of money in his direction, providing unquestioning support for most of his reign. Gloria Macapagal-Arroyo drew a substantial upgrade in US aid by casting herself as a loyal ally in the GWOT. There were real hopes in some circles that casting the Philippines as the first line of defense against the red horde would bring in a bunch of high end military equipment and a bunch of money, and there was some real disappointment when that did not materialize. Apparently the US diplomats and agencies are smarter than they once were.
Again, lack of context leads to misunderstanding. Throughout the tribal regions in the north (where I live), the Manila government is seen as a colonial power, trying to push its way in and grab timber, minerals, hydropower. People here fought a substantial war against the government from the late 70s through the early 90s. The town I live in was under virtual military occupation for a number of years; civilians were killed and there were many human rights abuses. There's peace now, mostly because the military stays out or keeps a very low profile and the big resource exploitation projects have been cancelled, but the people still see the Philippine military as a threat and the fighting could easily resume.
That's not unique: a long history of corruption, elite domination, and human rights abuse leaves large numbers of Filipinos seeing their own government as a major threat - and certainly a more immediate threat than China.
You might want to read up a bit on the nature of Philippine "democracy". I can e-mail you an article on the subject that makes a good start point, if you like. The online version is behind a paywall.
What I said was that many Filipinos do not see the US as a dependable ally, not that "Philippine does not find the US a dependable ally".
I think Filipinos would be wise not to depend on the US to do whatever Filipinos want them to do. The US will act according to its own perceived interests.
The US has already made it clear that they've no intention of providing weaponry competitive with any regional peer, and that they will not take sides in territorial disputes. The treaty, as discussed before, obligates nothing beyond response "in accordance with constitutional procedures", which guarantees nothing. If US constitutional procedure concludes that the appropriate response to an incident is a diplomatic protest, that's all they are obligated to do.
Whether or not that makes the US a "dependable ally" depends on what you were depending on them to do in the first place. I think the Filipinos can depend on the US to at according to perceived US interests at any given time, which is all you'd expect from anyone in the realm of international affairs.