I think something happened to Shep when he was covering Katrina; ever since he has been one step away from the looney bin and has a hard time dealing fairly with Republicans he interviews on his show.
I watched shep and I thought he was a step away from OLBY. He seems very unhinged in all interviews.
Interesting observation, where you make the time cut-off in Shep’s behavior. I didn’t watch him previously, so I can’t say.