Name-calling is always bad. However, when mature adults indulge in this behavior, there is usually a good reason. Sometimes, it is absolutely unforgivable.
Hong Kongers call Mainland Chinese locusts. In retaliation, a Beijing lecturer Kong Qingdong(孔庆东)called Hong Kongers dogs. I can understand the frustration from both sides. However, when a foreign scholar who has benefited from Singapore's generosity (8 years of free education when most Singaporeans graduate with heavy debts) can say "There are more dogs than humans in Singapore", this is totally unforgivable.
Singaporeans must realize that we stand on the moral high ground in condemning Sun Xu (孙旭)'s ungrateful behavior. No Mainland Chinese in his right mind can support Sun Xu (孙旭). He has not only insulted Singaporeans but has brought shame to his family and his home country China. How can any Chinese or any human support him? When we scold Sun Xu(孙旭), we should take note not to extend the condemnation to other Chinese. Otherwise, we lose the moral high ground. Focus the fire on Sun Xu. The other PRC scholars and PRC foreigners in Singapore are innocent.
Some prominent people whom I respect in Singaporean society said Singaporeans have gone too far in condemning Sun Xu (孙旭). They probably just read mainstream media and are not aware of the full situation. To judge Sun Xu (孙旭)'s sincerity, see what was his initial reaction when asked by a Chinese tabloid about his remarks. His answer was "I am only complaining. It is just a small matter and I do not want to blow it up. Anyway, I have already deleted the comment." This shows he is totally unrepentant. The worst is this: when a fellow blogger warns Sun Xu (孙旭) to take down his dog comment because Singapore patriot Alex Tan may come after him (which he did by making a police report), his written reply in black and white was "I will wait for him with a dagger".
Sun Xu (孙旭) has apologized. Of course he will apologize to protect himself. He is only 2 months away from graduation and is afraid that his scholarship will be revoked. He is apologizing for self-preservation. Do you think he would apologize if he were some S-Chip CEO residing in China and the local authorities cannot do anything about him? Do you think he would apologize if he had already graduated from NUS and returned to China?
For the good of everyone including Sun Xu (孙旭), I sincerely think his scholarship must be revoked. This is what we Singaporeans owe to the Chinese people and Sun Xu (孙旭)'s parents. The reasons are written in Chinese because it was written from the perspective of a Chinese citizen (just play make-believe).