A bit of context on this: The Australian arms of Target and Kmart are owned by the same group, Wesfarmers. If something gets pulled from one, it generally gets pulled from the other. So it's not really indicative of building momentum to a ban.

But if you ask me, GTAV getting pulled probably has less to do with the petition, and more to do with pre-empting the outrage Target would've suffered if people had noticed this earlier:

That's the top of a full-page ad in the largest national newspaper, advertising Grand Theft Auto V as a children's toy. Because videogames are for children, don'tcha know.