Yea just seen that. http://www.bbc.com/news/world-asia-38906821 All to common occurrence unfortunately
Coincidentally, It seems to happen when there is a whiff of land being sold, and squatters don't move on too quickly.
Id like to think that isnt the case but you may well be tight. I have read CDN on occasion and they usually do give squatters a day when the shanty will be torn down. Obviously with no provision for accomodation.
I've driven through that area and it certainly is deprived but look at the pictures a lot of those homes are two or three story breeze block some with ornate balconies on the first and second floor, it is not very different to parts of Paranaque that I know well. A lot of people that legitimately owned land and property will have been hurt by this as well. In Paranaque you have properties that look like squats but which are actually built on ground owned by locals and rented out, rents being as low as 1000 peso a month. I do think you are right, arson is a time tested way of clearing ground for property developers and not just in the Philippines, I have seen activity in Glasgow that looked extremely suspicious when placed in context, listed city centre buildings suddenly burning to the ground. At least in Scotland the fire services are not complicit.