I think the point is that despite what thermal image has to say about the subject, there has been a huge rise in monthly rental costs in the last 18 months in Singapore. An apartment that cost S$3000 last year now costs S$5500. The rental allowance has not kept pace with the rises.
Why would anybody travel thousands of miles and relocate their families to move into an HDB, which is essentially a very clean, well maintained council flat.
You can argue the rights and wrongs about hiring expats. I feel sure that if situations were reversed there would be major industrial unrest, but the bottom line is that you get what you pay for in terms of quality. The best people will inevitably go for the best package. Its simple supply and demand.
I appreciate that some locals object to housing allowance being paid to expats but the bottom line is that expats are applying to a job offer, not setting the policy. If you don't like the policy object to the company not the individual pilots, who are only trying to make a living.