My take would be something like this: Any public or public-ish website, or website with more than x user which presents algorithmically sorted or curated content must make readily available the source feed for their algorithms as well as any other information they use. On any page where algorithmically sorted or curated content is presented, they must fully describe the algorithm used. Ditto anywhere you select an algorithm or navigate to an algorithmically curated or sorted page - it must be described fully in the button or selector, or adjacent to it. If that is impractical for space reasons, it should be described as best as possible with footnotes expanding on the explanation. Furthermore, the explanation, source feed, and additional information should be complete and clear such that someone could reasonably recreate a page or sorting given the algorithm, source feed, and additional info. This would be the test used in court if someone alleged infringement.

My hope is that such a law would heavily bias sites towards simple, less manipulative algorithms.