Yeah, he backtracks on pulling US troops away from Mindanao. That Island is called the Wild, Wild South. Though there are Marxist Communist insurgents (NPA, New People's Army) they are a drop in the bucket compared to the MILF, MLF, MIM (all Moro Islamic extremists vying for autonomy and secessionist self rule from the Republic) and now the Abu Saayef (ISIS sympathizers). [I've seen Moammar Ghadafi bumper stickers on jeepneys.]
Ad to that the anti-communist vigilantes (Alsa Masa) which were centered around Davao where Duterte Harry is from (I wonder which side of that scrape he hails from...). Maybe he sides with the NPA. Could explain his lean toward China. 
When Corry Aquino got elected after Ferdinand Marcos' exile, she pandered to her slain husband's (Benigno was assasinated on the tarmac at the Manila Airport) commie buddies. Before the 99 year lease was up on the Subic Bay naval facility and the Clark Air Base, she allowed Russia to establish a naval drydock on northern Luzon.