There are other, non-punishment related ways to reduce the future likelihood of Rowling's anti trans behavior. I'd suggest a combination of extinction and DRI (differential reinforcement of incompatible behavior) might be better approaches with less problematic side effects.It seems like one could easily agree with the Harper's Letter and also advocate publicly that Rowland's behavior and ideas are harmful and she should lose her status as a cultural touchstone for her tone-deaf and misinformed opinions. Perhaps where there is some disagreement is whether Rowland should be punished.
I think one's response to the question of punishment has to do with differing objectives in the situation.
Some possible objectives:
1. Stop Rowland from spreading and validating harmful ideas to others. (punish ok!)
2. Change Rowland's mind. (punish not recommended)
3. Stand up for those harmed by Rowland's speech. (punish ok!)
4. Virtue signal. (punish ok!)
5. Discourage others who agree with Rowland from speaking up. (punish ok!)