Chocks Away - I think that you don't like SIA period, doesn't matter what they do or don't do or any of their policies?
The 'Singaporeans Only' policy goes back to ( at least) the introduction of the B747-400 in 1989, it was later relaxed when there were simply not enough qualified Singaporeans to crew the fleet, the airline was expanding rapidly and took delivery of 52 -400 aircraft.
SIA is the national airline and it has always been their policy to put their own Nationals first, if you look around the world you will see this is not an uncommon policy. Singaporeans comprise people of Indian, Malay and Chinese ethnic roots, possibly some other ethnic backgrounds too, I flew with SIA on the -400 for ten years and I think your fears are groundless.