You know what's sad? Watching someone you once respected devolve into an unserious, irrational partisan. It makes you wonder if maybe that's what they were all along and you just didn't see it or didn't want to see it. An alternative possibility is that they really were a different person when you first knew them, but the ideas they embraced eventually came to full fruition in their lives, changing them into someone different from the person you originally met. Either way, it's a difficult reality to accept.