You refer to the ruminates who intentionally bring up and chew their cud over and over precisely because the iterative process they're engaged in allows them to break down and digest the material over time? And indeed is the only possible way they can "work through" the material?

The hubris to suppose those who ruminate are doing it simply to pass the time...

Yes. Colloquialism. I'm learning that this might be regional that the phrase ruminate where I live means unproductive dwelling on something. I understand the process that the animals use.

It's a thing that means only part of the thing (honestly, pretty close to the opposite of the things?). Again, Apparently that's regional and I'm just now learning that.