> Wikipedia articles should be based on reliable, published secondary sources, and to a lesser extent, on tertiary sources and primary sources. Secondary or tertiary sources are needed to establish the topic's notability and avoid novel interpretations of primary sources. All analyses and interpretive or synthetic claims about primary sources must be referenced to a secondary or tertiary source and must not be an original analysis of the primary-source material by Wikipedia editors.
Primary sources aren't completely disallowed, but they are definitely discouraged.
"The concept of primary, secondary, and tertiary sources originated with the academic discipline of historiography. The point was to give historians a handy way to indicate how close the source of a piece of information was to the actual events.[a]
Importantly, the concept developed to deal with "events", rather than ideas or abstract concepts. A primary source was a source that was created at about the same time as the event, regardless of the source's contents. So while a dictionary is an example of a tertiary source, an ancient dictionary is actually a primary source—for the meanings of words in the ancient world."
"All sources are primary for something
Every source is the primary source for something, whether it be the name of the author, its title, its date of publication, and so forth. For example, no matter what kind of book it is, the copyright page inside the front of a book is a primary source for the date of the book's publication. Even if the book would normally be considered a secondary source, if the statement that you are using this source to support is the date of its own publication, then you are using that book as a primary source."
It was an interesting read. Go ahead and do read the link.
Perhaps the jist is more about 'Primary' means different things to different groups in different context. And just saying the plain sentence "Wikipedia doesn't use Primary" is a really shallow incorrect take.
"For example, a memoir is a primary source when it is used to study its author's life or personal relationships, but the same text becomes a secondary source if it is used to investigate broader cultural or social conditions. Thus, the categories “primary” and “secondary” are relative and depend on the historical context and the purpose of the study. "Primary" and "secondary" should be understood as relative terms, with sources categorized according to specific historical contexts and what is being studied."
Primary sources aren't completely disallowed, but they are definitely discouraged.