In Vietnam, which is seen as socially progressive on LGBT issues and where a vibrant gay scene flourishes online and in some big cities, hopes for marriage reform have stalled.Why would Vietnam be "socially progressive" on this?
As far as mainland China is concerned, the report notes:
Homosexuality was officially decriminalised in 1997 but only taken off the list of psychiatric disorders four years later.
“Taiwan and mainland China have the same roots and culture so it suggests that Chinese society could also accept the idea of gay marriage,” said Li Yinhe, a renowned Chinese sexologist who has pressed Beijing policymakers on the issue.
There have been small signs of progress. While a Chinese court last year ruled against two men seeking to marry, the fact the case even made it into the judicial system was seen by many as an achievement.I still say that the gender imbalance in China is likely to influence attitudes, in the long term, towards gay relationships.
Update: here's a 2015 article from the ABC noting the surprising tolerance to gay rights activities being shown by the government in Vietnam. I hadn't noticed this at the time.