S.P. the answers have been to different questions. "Why can't I have a particular runway?" is not the same question as "why is that the assigned runway?". Noise abatement procedures require us to assign particular runways:
AIP noise abatement procedures:
ENR 1.5-40, 9.1.2 (page 192 of the PDF):
https://www.airservicesaustralia.com...ip/enroute.pdf
ML specific noise abatement procedures:
http://www.airservicesaustralia.com/...MLNA01-129.pdf
Porter, explaining why things are the way they are isn't supporting it. If you don't know why things are how can you change them or realise there's a lot more to it than you thought?