Sounds like a bad idea. Bad actors would immediately exploit it and figure out how to most effectively flood everyone with spam, same as if Google's exact algorithms were public. Not everything has to be open.
Fortunately this has not turned out to be the case in reality. If there are flaws in the system they will probably be easier to find and fix with more eyes on it.
In content moderation vs spammers, you have spammers adapting to your tools in real time while posting content in the same way real users do, and the balance between "don't want to accidentally ban real users (who post stuff very similar to the bots)" vs "does it matter if someone gets past your defences a few times an hour" is massively different too.
The problem with google search isn't that people are exploiting 0-days that the developers aren't aware of. The problem is that the majority of the internet is becoming nearly identical pages that do the bare minimum to get ranked by search engines. Making the algorithm public will only exacerbate that
You assert that more eyes on the flaws would make the issue worse rather than better, but i disagree.
Further, compromise of one box typically does not render all of them running that OS useless and harmful.
Especially not if the top choices were fundamentally different from each other.
It may go so far as to make it significantly more difficult for bad actors to operate.
Let's stop the Communistic mentality around keeping things hidden. Please read about Soviet Russia, about Siberia and how Russians had no idea about the miseries inflected on them for decades.