There is no wrong choice. The right choice is whatever they pick. Its not Hermione’s place to brainwash her parents and force them to do something against their will.
Brainwash: make (someone) adopt radically different beliefs by using systematic and often forcible pressure.
She didn't brainwash them, she just made them safer because they'd have no recollection or connection to her anymore. That's the right choice to me, making them leave to Australia is forcing them to do something against their will, she didn't make them do anything.
She used magic to make them forget who they were, and to put the idea into their head that they wanted to move to Australia. That is brainwashing, and that is forcing them to do something.
I thought it was just wiping their memories, this is closer to brainwashing, but giving someone a new identity for their safety before bringing it back can't be considered the wrong choice.
It can if you don’t give the person a choice. If Hermione had died, her parents would have gone their whole lives without knowing who they really were.
Because if she'd died, the Death Eaters might have taken over and hunted them down if they had a connection to Hermione, removing said connection kept them safe.
