If you require them to tell you exactly what algorithm they use
And give you advance notice, everyone - from legitimate news sites to troll farms / fake news / conspiracy sites - will know how to game the system. How is that going to help anyone?
The reason they change their algorithm is because people have figured out how to game the system, so they have to work around it to eliminate that gaming. Sometimes it hurts legitimate sites, that's too bad but I don't see how it could be avoided.
The original PageRank was genius, at first it did a great job of showing the most useful links. The problem was it was incredibly easy to game and falsely inflate the ranking of your site, and the war has been fought between search engines and SEOs ever since.
Biting the hand that feeds IT
