I'm having a hard time understanding what's bad about this. If they are otherwise unemployable, then it's good that they are doing this isn't it?

What's bad is that they are often nearly disabled, and if they don't do this, they starve.

No social security for the elderly in Singapore.

If they're not doing anything actually productive, wouldn't it be better to pay them the money and let them spend the time on something they enjoy?

Singapore Cleanliness is a huge mental relief after having to deal with the disgusting mess that various parts of San Francisco are. Keeping this city/state clean is incredibly productive. There is a reason why a story regarding hiring cleaning consultants makes the front page news, and people are fined $15,000 for throwing out cigarette butts - singaporeans take cleanliness very, very seriously.

Cleaning toilets isn't productive labor?

Not if they're already cleaned plenty often enough and it's just busy-work, which was what I understood the parent comment to be claiming.

Without basic income, that's the closest you can get.

Half the time? Are we perhaps engaging in a bit of hyperbole here? I can't recall the last time I recall a public washroom being cleaned that I wanted to visit - starting at Labrador Park (which actually can get kind of messy), and moving up through One North, Bishan, and Orchard. Occasional visits to Bugis - I'll try and visit them every day for a week or so, and see if they are every being actively cleaned.