Perhaps in the past people had ethics and so it didn't need to be stated. I'm surprised they need it in the rules, as I would expect since they pick the jury they pick people with ethics. But then I'll admit complete ignorance to how they do anything (and no care either since I'm not a movie person)

Online reviews don't have enough control over their reviewers and so it only takes a small number of unethical people to cause a big problem.

They've discontinued mailing out screeners and members have to watch them through the private Academy Screening Room streaming service. The academy now knows who watched what and can use that data for fair voting.