Compared to her Republican counterpart she is.
What you can't understand is that many states are like Missouri in that they won't elect your kind of progressive. In order to take back the House, Democrats are going to have to win in places like MO. The electorate of that state chooses its representatives. If you loony Bernsters have your way, there would be two Republican Senators from Missouri. Each would be leagues worse than McCaskil.
I expect the good progressive Congressmen from Oregon to work with her on issues where they can agree. She votes in favor of progressive issues 68% of the time. That's much better than her counterpart, Roy Blunt, who votes favorably for progress only 3% of the time. If I lived in MO, I'd hate her. Because I live in Oregon, I'm glad for her because her Republican replacement would be far worse. It's up to the people of Missouri to choose their reps. I don't know why you have such a hard time with the concept of local representation as a cornerstone of democracy.