Edit: Looks like the science publishing company is "operated independently", despite family ties - https://media.springernature.com/full/springer-cms/rest/v1/c...
Axel Springer is the company that bought Politico (and produces rags like Bild in Germany).
Springer Nature is majority owned by Holtzbrinck, a competitor to Axel Springer.
Besides which, this is a summary of a research paper that DID include OpenAI on the list. Omitting it is one of several choices that change the takeaways of the paper (linked above), which did a much better job at acknowledging and sorting the benefits of different varieties of "open"-ness.
Overall, TFA takes a cherrypicked scope on the naming controversy that hides the fact that some participants are contributing much more to public research and access than others.