Telstra is no more in favor of free market deregulation than the RIAA is in favor of P2P file sharing; it's always jockeyed for legislation that would give it preferential treatment over its competitors. Telstra doesn't want structural separation because it has owned most of the telecommunications infrastructure up to now. They want to retain that control, because everyone will have to dance to their tune, as is currently the case, where ISP resellers must charge higher monthly rates if they use Telstra's over-priced infrastructure.
Telstra is the most expensive ISP in Australia, charging for BOTH uploads and downloads. This would make sharing on winmx or torrent a losing proposition because everyone who might upload from you would add to your quota.