Edit: Looks like the science publishing company is "operated independently", despite family ties - https://media.springernature.com/full/springer-cms/rest/v1/c...
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.
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.