I imagine you had a large amount of loyalists.
Theres a reason why the Hindu/Buddhist Devout IG trait is one of the strongest in the game. Just having a Level 5 Dedicated Police Force alongside them having +10 approval right then and there directly results in you getting zero radicals from lose of standard of living. Where it starts to get broken is that once their SoL drops? Well, that can start rising again....which increases the amount of loyalists in said pop. Where it really gets broken is the fact that one of the causes of SoL drop is that the pop got fired for some reason...like say you just switched all of China's industries en-mass to a better PM, causing 500,000 people to suddenly get fired as the building wants less laborers and more mechanics. Normally, that would actually cause a large spike in radicals...but for China, its a spike in Loyalists. Keeping the Devout Happy is a legit good idea as China due to the resulting ability to just ignore radicals and have very happy IGs due to literally tens of millions of loyalists once the gravy train gets going.