This is a very interesting post by Charwill, however, I believe that the court interpretation must be open to dispute.
I am sure that in law it must be arguable that if a Filipino, who is divorced by his/her alien spouse, is free to marry then the converse must apply, ie where the Filipino spouse divorces his/her alien spouse he /she must equally be free to marry.
In this later case the alien spouse would be free to marry, as they would in the first case. It is arguably ridiculous to treat the Filipino as still be considered as married if his/her spouse is treated as no longer married. Who would they be married to?
I hope a prominent Filipino lawyer chooses to appeal such a case to the high court.
I don't know if international human right law applies to the Philippines, if it does the present court finding must be reversed.