A well written article.

From my understanding, it is largely Senator Conroy who is trying push this through (for reasons I cannot fathom). It has been noted that if the current Australian government were to be replaced by the opposition, the Minister for Communications would have to be replaced. Helen Coonan (the past Liberal Senator responsible for it) was also in charge of implementing a filtering scheme - http://www.netalert.gov.au/ (The state of that link will inform you how successful that was.)

I'm uncertain whether replacing Conroy would curb internet filtering in Australia, or merely change it's focus once more.