> (Also, Wikipedia is a tertiary source, as it is meant to only cite secondary sources, not primary sources.)

Wikipedia absolutely cites primary sources (as well as secondary and tertiary sources), and this is in accordance with their policy. Breaking news stories and scientific papers are some commonly used primary sources. You may be thinking of their "no original research" policy or their warnings against editors adding their own interpretation to primary sources.

Perhaps I was a bit strict, but Wikipedia is mainly meant to cite secondary sources.

When they explain where primary sources are allowed, they emphasize they "should be used carefully":

https://en.wikipedia.org/wiki/Wikipedia:Identifying_and_usin...

Also "Wikipedia articles should be based on reliable, published secondary sources, and to a lesser extent, on tertiary sources and primary sources."

https://en.wikipedia.org/wiki/Wikipedia:No_original_research...

The general idea is that primary sources have not been judged as notable by anyone. The fact that a secondary source considers it notable to include a primary source is a strong signal that the information has passed a first, minimal bar for inclusion in an encyclopedia.

And when primary sources are cited, Wikipedia is exceptionally clear that they must be cited only for verifiable statements of fact, not interpretations or synthesis. That's what secondary sources are for.