At the risk of overcomplicating an astute observation, I'd say that there are actually three aspects: game knowledge, maneuvering, and metagaming. That is to say that the ability to understand your opponent is fundamentally separate from one's ability to effectively foil them.
Iceworld embodies the platonic ideal of a maneuvering test by massively compressesing the total number of possible gamestates into a 3x3 grid of sightlines. The map itself isn't exactly a masterstroke, but it's nonetheless extremely impressive in the way that it manages to avoid collapsing into degenerate gamestates after jettisoning so much complexity.
At least some CoD maps like Shipment, Shoot House and Rust have a bit more complexity, places to maneuver, and, yes, even camp for a short while. The biggest thrill is always rushing to the top of the tower on Rust, where you feel you have a clear advantage, and conversely, taking revenge on that pesky tower camper.
I haven't played fy_iceworld, but think that boiling that formula down to where there's absolutely no place to hide, removes any strategy at all, and staying alive becomes a matter of luck, rather than skill.
*RA3, a Quake mod which came out around the same time as CS, lowered the skill floor by giving players a full loadout of weapons and maximum health on spawn. It was good!