I don’t disagree. John Dixon can say what he likes about whatever he likes.
An elected official should not. If he’d kept two different accounts (one personal, one professional) I doubt this would have happened. But because he gave the appearance of a council official being critical of a group of people, I think it’s right that he should be reprimanded within the rules.
I don’t think we should prioritise religious sensibilities. But given that we do, I don’t see how a Scientologist making a complaint is any worse than another religion.