Actually, I know a woman born and raised in the good ol’ USA who of her own free will, at the age of 27, married a man 50 years older than her - yes, old enough to be her grandfather. Apparently, they’re very happy together. Odd, but not unheard of or impossible.
Also, living in a city like Chicago for 15 years I met a lot of folks either born in the US or primarially raised in the US who nonetheless also came from cultures where arranged marriages were the norm. 18, 20, 25, 30 year old American citizens, both men and women, consenting to marriages with people they had never laid eyes on although they had all the freedom in the world to do otherwise. Nor are these people living uneducated in some ghetto - I’m talking about folks with MBAs from prestigious universities working as executives, doctors, lawyers, etc.
Sometimes it works, sometimes it doesn’t.
I DO know that history shows that when the Great White Benevolent People step in and start picking and choosing parts of a culture to keep or discard that, in general, things are only made worse. Indeed, they might even wind up reinforcing the very cultural practices they seek to discourage.
It’s western culture that dictates marriage is about romance and love - in many other times and places marriage was about producing babies without marrying too close a cousin, or political gain, or other things. Happiness was a bonus, not an expected thing or a right. Even the couple I mentioned in the first paragraph - yes, I suspect there were ulterior motives on the part of both parties beyond just romance. So what? If all parties are content with the situation and gain from it, it’s none of my business.
So… what it comes down to is, is the Aboriginal girl really being held against her will or not? Was her “I don’t want to stay” really I don’t want to stay here tonight or I don’t want to stay here at all? I’ve got a sister-in-law who married at 18 (not that much older than this girl) who frequently runs back to mama after a fight with her husband, but is still married to the jerk after a couple decades and two kids. There is nothing stopping her from terminating the relationship - but she doesn’t.
As I said before, I clearly don’t know the whole story. While it’s tempting, due to my background, to condemn this marriage I can also see that there are elements that make me suspicious this may be as much a conflict between the girls parents and her husband as between the girl and her husband. I just don’t know.