Ok, but you'd agree that we shouldn't allow, say, an offensive word for a specific race to be used right? Because that would be actively harmful to many people.

Ok, but you'd agree that we shouldn't allow, say, an offensive word for a specific race to be used right? Because that would be actively harmful to many people. So we make a rule saying "you can't use word X". So someone submits a plate that is X but... with a number replacing a letter. It's not against the rules, but it's still actively harmful because a human subjectively reads it as the banned word. So you expand the rule, but then language changes, etc etc. Surely you need to have a subjective judgement process because the interpretation/harm is subjective? I'll grant you that finding the right balance here, or where the line is, is a hard problem. This list to me however shows that it can be achieved in a reasonable way. Alternatively if you think that people should be allowed to use widely recognised, highly derogatory words for other people as number plates, that rules like being 6 characters is strictly sufficient, then I think we disagree too much to resolve.