Why would you want to live in a country where you can’t converse with most of the population? Or is “residence” about having a bolthole and a convenient way to dodge Chinese taxes by claiming to live overseas?
Two very good questions.
1: Beats me, but plenty of people do. Just pop down to Sanlitun on any given evening and you'll see the Beijing edition of people who move to a far off land and make no effort to learn the language or fit in to the local society.
2: Can't comment on Donghua Liu's case, of course, cos I don't know the guy, but there's no shortage of Chinese people who can afford it getting out, or at least, getting their families out of China. There are many reasons for that, having a convenient little bolthole is one. There are worse reasons (fleeing likely arrest for actual crimes) and better reasons (preferring the better environment or more relaxed pace of life). Liu's involvement in a corruption case in Chongqing has been reported, though it should be noted he was a witness and wasn't prosecuted. So let's give him the benefit of the doubt for now and assume he just finds NZ a more pleasant place to live than Chongqing.