her status and authority, unfortunately, make her an acceptable target
Agreed, but It's really more that she's a complete arsehole. As a nimby mining magnate, she is a sponsor of organised climate denialism and vocal about it herself, a race she clearly has a horse in. She's also an active libertarian who wants to further dismantle the welfare system, and reduce taxation, and wants Australian workers to be cool like Africans and work for $2 a day. And a vocal Trump supporter.
It's not the painting that makes her ugly, it's her behaviour and ideology.
Australia’s richest woman seeks removal of her portrait from exhibition ( www.cnn.com )