It’s simply a question of cost/benefit analysis. A Pinoy person who wanted stay in Taiwan would know they could never become Taiwanese. It’s only a damn feck Westerner who would think that they could ever be accepted as normal as a non-Taiwanese in Taiwan. Someone from SE Asia would know that could never happen.
I would assume (I might be wrong) that a Pinoy would just calculate how much they could make for their family and future back home, here in a country where they have a higher income and practically no day-to-day expenses. If that meant breaking the law (God forbid! Breaking the law in Taiwan! What a travesty!!!) then they would do it…making - and saving - money until they were deported.
The Taiwanese government knows that, so they try to control and monitor the inward flow of economic migrants. If they focused on the outward flow, creating a financial penalty for poorer-country overstays, that would only create a burden for Taiwan to support the non-conforming illegals who couldn’t pay the overstay fee and thus had to be detained in Taiwan.
So instead, SE Asian overstays are blacklisted and detained for a few weeks. Then they’re shipped back home - where their money has already been remitted.
In short, there is no real penalty for a SE Asian person for overstaying in Taiwan, if they think that they can’t stay or return here legally.
Hence, why not?