I think the problem with the Polanski business is that several different arguments are going on. Some are particular to the actual case itself (was the girl willing, was the plea bargain valid, would the extradition be lawful under Swiss law) others are broader and address the concepts behind the case (age of consent, statutory rape, extradition). Things get tangled because some are arguing over the underlying concepts, where others agree about the philosophical underpinnings but disagree about the facts of this particular case.
And it's all maximized because of the unpopularity of the parties involved--a skanky girl, a rich "Hollywood elite", big bad bully America, and snidely snobby Switzerland. Plus all the artsy-fartsy film types and the "think of the children!" types adding to the chaos. And a truckload of lawyers and judges, making deals and things. It's a recipe for an argument that can never be resolved rationally because there are simply too many irrational tangents to go off on.