Plenty of other explanations.
(1) he has never been up for nominations before - never! - so any fans he has are not all cashed out after voting for him, week after week, like Priya's and David's may be by now.
(2) Nathan Joliffe, the winner of Celebrity Apprentice and general party boy around town, encouraged his 20,000 twit followers to vote for Steggles (I'm sure I read it here, so it must be true)
(3) he is quite cute
(4) he provides conflict, therefore content
(5) he is dismissive of Travis - this may win him some points
(6) maybe he has lots of actual fans
(7) the Frozen Chicken, for art connoisseurs
Priya got 40% of the saves the first week she was up. Travis got 37% last week. David got 30% a couple of weeks back. Maybe people like Ryan, too, and this is their first chance to show it?
Those looked like private school uniforms in the clips they showed early on, so maybe the folks are coughing up, too. But he seems pretty well connected, in the Australian low-grade celeb scene, being friends with Matt from last year and Nathan Joliffe and someone else. Probably Ryan Buckingham! Maybe they're all twitting their arses off, encouraging people to throw votes his way.