The Kerchers, the Knoxes and Sub-judice, plus some stuff about what people wore
In the UK, (which I'm not claiming as some paragon of justice, it's not!) we have strict rules about sub-judice contempt, which means that from the moment of arrest to the point of conviction, the media can't publish any material that might be deemed prejudicial to the jury, witnesses, or (non-professional) judiciary. (These laws do not cover legal proceedings in other countries- the Kerchers, as well as all the tabloid smears in UK tabloids are fine there!). If, in the UK police leaked prejudicial info to the media, they could also be charged with contempt under the sub-judice rules.
One of the differences between the Knoxes and the Kerchers is that the Knoxes come from a country where there aren't sub-judice rules and the Kerchers come from a country where there are (Again, not saying they are bound by those rules in this case, merely that this is their frame of reference). Another difference is that the Knoxes felt compelled to talk to the media extensively as a response to the dreadful smear taking place in the media with the collusion the police which is an absolutely classic example of why we have sub-judice rules in the UK.
Generally speaking though, I think it's clear that even without the background of this smear, the Knoxes public statements are always going to be less prejudicial than the Kerchers'. This is because, although a lot of posters here feel that an attitude of impartial objectivity as to who committed the crime is too much to expect from the Kerchers, people do expect families of victims of crime to want the person/ people who actually committed the crime (and only that person) to be found guilty and sentenced accordingly- they want a result that reflects the truth. Therefore, when the family of the victim speak out against defendants, people who don't have a detailed knowledge of the evidence will think that statements such as the Kerchers' must reflect the truth. On the other hand, people don't expect the families of defendants to be as interested in the truth, and will always expect a bias in their statements- therefore the Knoxes statements (and the Sollecitos') are not as prejudicial.
There is also the fact that has already been pointed out by posters here, that for the family of the victim to equate justice with a guilty verdict, and taking a public opinion on the actual evidence is an emotionally manipulative strategy which has the effect (intended or not) of making it difficult for people to question evidence and guilt.
Again, in the UK, the only place for the victim's family in a courtroom is to testify as to the effect that the crime has had. Anything more than this involvement would be too biased and partial and subjective. In some countries, victims are more involved in the sentencing phase and this is at least slightly more appropriate (at least the defendant should be guilty beyond reasonable doubt).
Finally, (on sub-judice) I'd point out that although in the UK sub-judice rules apply to the point of conviction / verdict, because appeals aren't automatic in the way they are in Italy, and extending them to the end of any possible appeal would be in effect to extend indefinitely, we can still say that if Italy had similar rules, we can say they should apply to when the verdict is either confirmed or overturned by the appeal court (to keep in the spirit of those laws, as the appeal in Italy is de novo etc).
I personally think that what's happened in the case of Amanda Knox and Raffaelle Sollecito and what is happening to Sabrina Misseri (and countless other people in the town) show the urgent need for some sub-judice rules in Italy. In AK/RS case, we might know that their convictions were overturned because there was never a genuine case to be made, but it is primarily because of the media coverage in this case (reporting prejudical material from the police, prosecutor, the Kerchers etc) that the wider public will probably think that their convictions were overturned because of technicalities / legal loopholes, and this perception will follow them around for the rest of their lives, sadly.
As to the dress of Amanda and her family, I'm reminded of an experience of my own. My aunt lives between Perugia and Gubbio, and so I've spent a lot of summers there. When I was 14, me and my family went to see the church at Assisi (just up the road from Capanne). Being used to English 'summers' I found the heat in Perugia in August almost unbearable, and on that day wore shorts and a t-shirt. On trying to enter the church my path was blocked by a guard with a gun screaming Italian in my face. My parents pulled me away out of the church entrance, apologised to me, and explained that the guard was saying that I couldn't wear shorts into a church. I couldn't understand why a child wearing shorts on a blasting hot day was 'inappropriate' and still can't. Like I say, my parents apologised to me for not having thought that my attire might be considered inappropriate. But they were intelligent people, who'd probably spent a total of about 2 years in Italy by the point, and they didn't fully understand the Italians' obsession with what people wear.
So I think the Knoxes have just not understood what absurd importance Italians place on dress and notions of respectability and modesty. My opinion only!