For me it wasn't so much that he was the only one to vote against it, as it was that when he did vote against it the people of his state promptly replaced him with a more Law and Order senator.
In the US we claim we want freedom, privacy, and all that good stuff. But where the rubber meets the road, it becomes pretty clear that we don't.
Feingold served another 10 years following his vote on the Patriot Act.