Are you sure you are Singaporean? If you are you should know very well that our universities are stuffed full of foreigners on scholarships paid by Singapore taxpayer money, in medical schools and various highly desired jobs.
There is no rule that companies have to hire Singaporean first, which is a law which many Singaporeans are begging for. Companies have been exploiting that and hiring cheap labor and kicking out good Singaporeans due to their higher wages and NS liabilities.
There isn't much you can do about it and the fact that SIA is owned by Temasek means it is even more protected...the government will not do anything to upset and put off foreigners coming into the country for the country to grow. The only thing you can do is to push for such Singaporean protection laws and hope for the best.