How come late night hosts always seem to think every guest did good shit whether a movie or book or whatever? Why not just be honest and say I thought this sucked. And get in a real discussion.?

Or like say hey this part in the movie I did not get can you explain it to me. Or ask something about their past or how they feel on being naked in a movie? I mean it would lower the pool of people who would come on, but it would be way better for their jobs showing they can be honest about shit instead of always pushing some crap movie or crap book or crap Broadway play? They always seem to come out years later and say yea that movie sucked it was a shit experience. Then the host could ask why the hell did you pick to do it to begin with?