In a muted way, the authors make clear that they do stand behind their findings:
In a retraction notice published today, the authors wrote that they recognized the validity of some of the complaints, including concerns about "the use of co-authorship as a measure of mentorship." The authors added that although they "believe that all the key findings of the paper with regards to co-authorship between junior and senior researchers are still valid," they "feel deep regret that the publication of our research has both caused pain on an individual level and triggered such a profound response among many in the scientific community."

Science News Staff, "Researchers retract controversial female mentorship paper" at Science
The journal, Nature Communications, claims that there are serious errors:
In this Article, we analysed publication records to identify pairs of junior and senior researchers working in the same discipline, at the same institution, who are co-authors on papers with no more than 20 authors. We use co-authorship, as defined above, as a proxy of mentorship by senior researchers, with the support of a survey that was targeted at a random sample of a recent cohort of researchers. We measure the quality of mentorship using the number of citations and the connectedness of the senior investigators.

The three independent experts commented on the validity of the approaches and the soundness of the interpretation in the Article. They supported previous criticisms in relation to the use of co-authorship as a measure of mentorship. Thus, any conclusions that might be drawn on biases in citations in the context of co-authorship cannot be extended to informal academic mentorship. The experts also noted that the operationalisation of mentorship quality was not validated in the paper.

AlShebli, B., Makovi, K. & Rahwan, T. Retraction Note: The association between early career informal mentorship in academic collaborations and junior author performance. Nat Commun 11, 6446 (2020).
The authors had clearly done their homework or tried to:
"The study, published on 17 November by researchers from New York University, Abu Dhabi, combed through more than 200 million scientific papers to identify several million mentor-mentee pairs, then tracked their co-authorships and citation records to evaluate the impact of mentorship."
But if Cancel doesn't like the outcome...

At RetractionWatch:
"The editors also say that they "have developed additional internal guidelines, and updated information for authors on how we approach this type of paper" and that, along with Sense about Science, as part of a dedication to diversity and inclusion in research, they have "launched as a pilot a peer review programme for early career researchers, consisting of a webinar and a hands-on phase which we plan to extend next year.""
In short, in future, issues will be addressed by bureaucrats who are careful not to trigger Outrage, Inc.

The bottom line is that — in a move worthy of an existentialist writer like Kafka — Cancel Culture has succeeded in making actual issues around mentorship dangerous to discuss. The big loser is equity, of course, because if one can't discuss actual issues (like guys are higher in the hierarchy at present), then one can't propose useful approaches. But there is always, of course, a bureaucrat out there (many, actually), quite ready to conduct a seminar, etc., which will change nothing because no one can afford to be honest.

See also: Cancel Culture tries to get a Nature Communications paper retracted We are informed that all science Twitter is in a ghastly rage over an open access paper in Nature Communications which seems to show that female scientists benefit more from male mentors than from female mentors. To a layperson with some life experience, that wouldn't be a surprising outcome at all. In a system that has been male-dominated since forever, more guys would be higher up on the pole. And if you want to get ahead, it pays to know Top People... But, of course, the Outrage Mob is sharpening the guillotine. Their final enemy is, after all, reality in any of its forms.