Yes, I think you're right, Malfie, although there are a lot of Britons who recognize the truth, too. There also are plenty of Americans who still think it's a case of a pretty, privileged white girl getting away with murder.
You're also right that media attention to cases involving young, attractive, sexually active subjects is common. You've noticed, though, that this case is set apart by the efforts of the innocence supporters, who by and large are educated, often intellectual, well-established members of mainstream society, as well as by the detractors, a minority of whom are from the same socioeconomic subgroup. It's true, murder cases don't always attract such intense interest from the non-tabloid-reading population.
I think certain people are drawn to the case because of its complexity. It entails not only the injustice of false arrest and false imprisonment, but also the misuse of international communications media, the misinterpretation of tenets of modern science, and serious failures of political representatives in both countries.*
Two primary realities of the case add to its challenges. First, to understand the facts of the case is to know Amanda and Raffaele are innocent. Thus, it becomes a fascinating, if frustrating, puzzle for supporters, who want to understand why the detractors display such strong resistance to the facts.
Second, the pitting of Amanda and Meredith against each other as if they are on opposite poles represents a complete and total misunderstanding and false view of the meaning of the case. Correcting that misconception in people's minds will be rewarding, once accomplished.
ETA: *I want to amend this to say political representative in the U.S. and legal authorities in Italy.