it might be the case that u are not residing in singapore. if u look properly, they DID state the following
CADET PILOTS (SINGAPORE)
PLEASE APPLY FOR THIS POSITION IF YOU ARE RESIDING IN SINGAPORE.
It is not true that you must reside in Singapore. The last time I checked, it states that the position is based in Singapore... not that you must reside in Singapore. There are many Malaysians who are SQ pilots too.