As the article also notes, they became very emotional when they announcement was made. That article may not have been the best example article to use. This one has more quotes from family members.
They include:
“It is ludicrous. How can they ignore all the other evidence. I thought the judge might play it safe and uphold the conviction but reduce the sentence. But this result is crazy."
and
“It makes a mockery of the original trial. We are all shocked, we could understand them reducing the sentence but completely freeing them, wow."
There doesn't seem to be any indication that the family has been at all shaken in their absolute certainty that Knox is guilty.
That is a better article, but I still don't think the parents are disgraceful based on that. They just believed the first verdict.
Which I believe is the point of a verdict. It's supposed to mean the accused are guilty beyond reasonable doubt. The parents followed the first trial, believed in it, and were of course emotionally invested in its validity.
It also sounds like they just need more time. They are in shock and don't know what to think:
What happens now? Does that mean the police have to look for more killers?
The poor grieving parents. They have ...
See: You Be the Jury, The Amanda Knox Test
While we hear about Bayes' Theorem being under threat in some courts, it is nice to savor the occasional moment of rationality prevailing in the justice system, and of mistakes being corrected.
Congratulations to the Italian court system for successfully saying "Oops!"
Things go wrong in this world quite a bit, as we know. Sometimes it's appropriate to just say "hooray!" when they go right.
Discuss, or celebrate.