Normalization only applies to the base tables, i.e. the tables which work as the "single source of truth". Queries and views (which are just stored and possibly cached queries) often have repeated information and this is not a problem. A data-warehouse is basically a cached query over the base tables, so again, normalization is not an issue.
The article seem to agree with this, but it is kind of buried in the text.
The article seem to agree with this, but it is kind of buried in the text.