By what measure do you come to that conclusion?
In purely sarcastic terms. Whilst QF have had a rough 12 months or so, extrapolate back a few years on there is quite a number of SQ incidents (that you don't hear about) and accident - if you go back as far as Taipei. I'm not sure who has the better record of the three airlines flying between SIN/MEL direct.
For EK, the problems seem to be with the A340 (JNB, MEL), don't know if it helps that MEL-SIN is a 777 operation.