I sort of get reddits reason to hold the post ranking algorithm secret. So that it is hard to game it. Until there is a way to easy 're-key' such an algorithm

I sort of get reddits reason to hold the post ranking algorithm secret. So that it is hard to game it. Until there is a way to easy 're-key' such an algorithm if someone found a way to abuse it, holding it secret is the best solution for them. I currently can't think of a better solution to avoid gaming of ranking algorithms than holding it secret and changing/adapting it often. Maybe some machine learning algorithm?