Joe Biden enraged by semi-tough but worthless questions; Jill Biden then cancels appearance
West apparently asked Biden a series of what might appear to be tough questions, and Biden responded by asking "who was writing her questions" and calling them a "joke". One of the questions was apparently "How is Senator Obama not being a Marxist?", and that's where Idiocracy comes in.
There's an excellent chance that Obama is not a full-on Marxist. However, his remarks certainly do reveal socialistic tendencies, and there's a world of difference between the two. In order to avoid being discredited while trying to discredit someone it's necessary to make that distinction. Otherwise, you're just putting on a sideshow while also helping the other side; see the list here.
She didn't discredit Biden, she just made him look bad. Real questions would have completely discredited him. And, because her questions weren't good enough, she gave the - if you will - libtards breathing room.
See, for instance, the Digg entitled "Joe Biden Destroys Neocon Anchorwoman", featuring comments that verge on "in fact, the Central Committee says..." See also the HuffPost's coverage: 
When doing things like this, ask tough questions, but make sure they're smart questions.
UPDATE: ThinkProgress says  West loaded her interview questions with right-wing smears, likening progressive tax policies to Marxism. Biden responded to West’s ridiculous line of questioning with disbelief...
If she had asked questions which were actually tough questions and she had pressed the issue to the point of discrediting him, they wouldn't be able to say that.
UPDATE 2: Let the "vetting" commence! The current top item in the Politics 2008 section of Digg is "Barbara West, Biden Interviewer: Her Husband is a GOP Flack!"  with over 1300 diggs. The HuffPost story above has almost 3200 diggs. The Youtube video linked at the top of this post has almost 900,000 views, but just 220 diggs.
Also, for posterity, here's the statement from the BHO campaign:
"There's nothing wrong with tough questions, but reporters have the very important job of sharing the truth with the public -- not misleading the American people with false information... Senator Biden handled the interview well; however, the anchor was completely unprofessional. Senator Biden's wife is not running for elected office, and there are many other stations in the Orlando television market that would gladly conduct a respectful and factual interview with her."
Translation: "If only we'd had known what was coming, we could have jammed the station's phone lines. And, don't do it again or we'll work to drive you off the air."
 blogs · orlandosentinel · com/entertainment_tv_tvblog/2008/10/wftvs-barbara-w.html
 huffingtonpost · com/2008/10/25/biden-slammed-during-flor_n_137830.html
 thinkprogress · org/2008/10/25/biden-marx-mccain
 bluetidalwave · com/2008/10/conflict-of-interest-orlando-journalist.html