The blog post itself says that... I think the person you responded to is asking if they have done anything to change the fact that their is zero review of any content posted, neither for accuracy of content nor ownership.
Udemy does do copyright reviews for approval to the marketplace but I think they are just contractors though, so I can definitely see how courses could slip by, with someone being unsure if it was a copyright infringement or just licensed content.
In my experience, the review process effectively just checks to see if you meet the technical requirements (at least 720p, at least 4h video content iirc), I uploaded four hours of a bbc miniseries(black mirror) and still had my course approved, though it was taken down around 6 months later (never published, was doing market research).
