I think you're underestimating how low salaries in Indonesia can be; 2.5 or 3 million is not uncommon. I see people literally going through trash. I see people working all day. Compared to that, SG life seems comparatively good. Even if you're able to send back just half then with 600SGD (the salary in the story) then you're still sending back a full month's wage for your family to spend, and it's quite likely you'll be able to send back more if you want.
I think some here are reasoning too much from their western perspective, and this isn't the kind of thing you really tend to see if you just visit for a week. Is it exploitation? Sure, I never said it's not. Everyone should deserve a reasonable minimum living standard, and it's sad I see so many people who don't. Yet at the same time, a lot of Indonesians still see as a "good deal" for them, exploitive or not, as it's just a better life than staying in Indonesia. This doesn't make it right, but it does explain it. There's a reason this women went back to Singapore after her negative experience.
In many ways, this is just as much of a failing of Indonesia's government who fail to solve basic problems as they're too busy siphoning money to their own accounts or getting lost in petty religious/ethnic arguments.