I have a theory about the abuse Oz players so often get in Scotland...
It just about always takes Oz players a while to adjust to the softer pitches and cold conditions of Scotland after playing on rock hard, zippy pitches in Oz. The cooler conditions allow for a faster pace and therefore less time to make decisions than they are used to. On top of that, there is the unrelenting pressure and scrutiny from media and fans. Some take longer than others.
Those who aren't instantly amazing cop abuse. And the reason Oz players cop more abuse than most (IMnsHO) is that Scots feel bullied and belittled by English fans re the standard of their league. They therefore respond in typical schoolyard fashion by bullying, in turn, those they regard as inferior to themselves. They don't regard Australia as a proper football country (despite our respective FIFA rankings) so they despise the A-League as shite and our players are pish. Any Oz player who doesn't immediately win the league for them reinforces this prejudice.
They can change though. I've seen on Celtic forums how contempt turned to love regarding MacDonald, Rogic, Mooy and (especially) Ange. It's happened on the Hearts forum re Devlin and Nieuwenhof... they've been especially bipolar re Rowles. The Hibs forum is up and down re Triantis and Miller (although Triantis is emerging as a fan favourite, as is Nisbet at Ross County).
Mind you, any Scottish forum can go from joy to outrage and despair (and back again) at any moment. They just really have it in for our players... until they don't.