I don't understand Russian so I can't really determine the accuracy of that post in terms of plagiarism but
When Hhampuz published the rules and talked about constructive posts, he meant constructive posts made by a campaign participant and not by a journalist of one of the news resources.
A post can be constructive and still have references to other sources. If I have some question and someone links me to a blog or just quotes some text from the blog I'd be glad that someone did their research and linked me to correct content.