Contradictions
1. There's a large and rather obvious contradiction between the rules being proposed and the claim that they "expect, and wish to promote, a cultural shift towards a general recognition that unidentified postings are not to be treated as true, reliable or trustworthy". If people can say what they want anonymously, then anonymous postings will be unreliable and will be ignored; if anonymous postings are subject to being taken down by anyone that complains, then anything that isn't taken down will be treated as rather more trustworthy.
2. "not regarded as credible unless the author is willing to justify or defend what they have written by disclosing his or her identity". This is stupid. The people who know best about something are often exactly the same people who have better things to do with their time than spend hundreds of hours "justifying" and "defending", and better things to do with their life savings than risk it in court. For example, if a business is ripping people off then you can be fairly sure that the business will diligently complain about every posting in which a ripped off customer accurately describes their miserable experience. But how many of those customers will be willing to "justify" and "defend", in court if necessary?