I have a good friend from the PI - she lives there but visits the US fairly often. Well connected large family. She said Dueterte is overwhelmingly popular and the main reason is his cleanup of drug lords and corruption. The drug crime and associated violence in the Philippines was absolutely horrific. So the Filipino people were fine with his methods.
We've had several neighbor (mostly elderly) die in home invasion robberies, a nephew killed in a hit in the crossfire by a politician who was trying to kill his rival, and a young girl killed by her jealous druggie boyfriend, not to mention people who died of “Shabu” induced strokes or heart attacks.
Duterte is popular because crime is down and he is now trying to remove the crooked cops and politicians.
The bad news: He is pro China.
The CIA has tried to undermine him the same way that the pro Russian president of the Ukraine was undermined: By using human rights folks and money to fund opposition newspapers.
I mean, the Human rights folks make a heroine of one crooked politician who took lots of bribe money from jailed drug lords, using her driver/lover. She is wined and dined, but here a photo shop of her and the driver have made her a laughing stock.