I never said that all prostitutes were from China or illegal immigrants. It's a real-life observation where I live. Specifically it is those who are from China and usually illegal immigrants that are soliciting in residential areas. A small minority of them are legally in Singapore accompanying their children who study on scholarship. Right around the corner where I live there are KTV bars where women from Mainland China claim to be customers, but accompany men they don't know inside to sing. They work out an arrangement and leave for a motel room somewhere, where it's not the KTV's business, when they in fact work for the KTV on an unofficial basis. Check your facts before you comment. There are local hookers who've lived in Singapore all their lives and they didn't start out as hookers either. And there are local teenagers who get tricked into gangs or start doing drugs and need quick cash. Do I need to mention all the possible subgroups of people who become prostitutes? Then there are the foreign maids who are in Singapore with a legal work permit who moonlight on their days off from domestic work. How am I stereotyping? If you don't know the situation please don't assume others are ignorant.
Whatever it is, the number still pales in comparison with the amount coming from Mainland China just because of their total population size. Even 1% of 1.3 billion is more than a million people (no, I'm not saying 1% of their population are hookers either).
I'm of Chinese descent myself and in no way am I being derogatory to Chinese women in particular. But you cannot ignore that this is a significant social problem. If you haven't seen it firsthand you won't understand why people are complaining about it. It's not a matter of discrimination against hookers or Chinese people. Don't make it about political correctness.
Most of the Mainland Chinese women I know personally are college-educated and some have more than one college degree.