What makes "invisible to everyone but you" a more "logical" interpretation of "shadow ban" than "banned but didn't tell you"? Are shadows invisible to everyone but you?
When a user is (normal) banned, they are normally told and their access/ability is restricted.
When a user is shadow banned they are normally not told they are banned and are still able to access and perform functions. I think this secrecy is where the word "shadow" comes in. The user is in the dark about the ban...