you're not getting it. favre's effort has nothing to do with the team's expectations of him, only the expectations that he has of himself.
the vikings or people like you may not hold favre accountable for his embarrassing effort on that play and i can understand that. but he should hold himself accounting because he is a football player, a teammate, and a leader.
i have seen hundreds of QB's make tackles on defenders after throwing an interception. did they have to? no, of course not, but they wanted to. that's my point.