I've seen this from time to time with CNN. On one hand they are very much pro-left. On the other hand you'll see a host break from the narrative and it typically results in this kind of shock from the guest.
Yeah, from time to time they break ranks, and it surprises the hell out of the guest.
See: Piers Morgan vs Toure ( I can't stand Piers, either), Brooke Baldwin vs Corrine Brown and now this.
I think there was just too much stupidity from the Trayvon situation for some of them to ignore. Maybe they realized how bad it was making American journalism look.