I don't like Shorten, but the quote is a lie, Shorten never made such a vow. I guess that's what you get for reading and quoting the australian! LOL, it's a loss making newspaper with its subscription base in free fall for a reason.
Shorten layed into Abbott for lying about cuts to the ABC, SBS and everything else, and Abbott layed into Shorten for not committing to reversing the cuts because Abbott failed to goad him into doing so.
Shorten has seen how stupid it was for Abbott to have made such a dumb unequivocal promise after what happened to Gillard, so at least he's trying not to repeat history.. again.