He wasn’t. He never encountered the Ring, at least not since Bilbo recovered it. He was corrupted by using a palantir to try to monitor Sauron’s actions.
The text is pretty explicit in saying this isn’t true of Saruman. He was a respected and honored leader of the Istari for centuries, before he turned.
I care. I like thinking about how the different parts of a work of art function together to create a larger whole. Which sometimes involves identifying which parts don’t actually add to that function.