Not too surprising - Asian countries are very culturally conservative. Everyone is expected to be perfect and filial, if they step out of local cultural norms they become a failure of their family. Westerners tend to look at the East through the lense of their own traditions which obviously foolish because the East is very different history and arguably, value wise. Western POP-culture obviously influenced the East but that's just marketing, the East still put it's own stamp on it and that stamp is made of iron. It's sad sometimes because it all seems so unfair and grueling but it's part of Asia's cultural evolution. The younger generations will eventually bring about the change they want to see, times are changing everywhere.
The entertainment industry in South Korea is insane(plus in China and Japan). They rip TOP apart just because he smokes weed! The least harmful drug among other narcotics.
When they see one little imperfection to a star, they would love to tear them down.