People should be very cautious complaining about the U.S. justice system in relation to the rest of the world.
Very careful.
The U.S. system is fraught with problems, no doubt, and I would love to see major changes implemented (no plea bargains, no deals to testify, jury trial if there's any threat of jail, acquitted on hung jury, and many others), but the U.S. criminal justice system compares quite favorably to the system in most other countries.
For example, in Italy, they can arrest you and keep in jail for a year on probable cause alone, without bringing charges or offering you bail. That's what happened to Knox (she did it, IMO).
Also, in many countries in Europe speech of various sorts is criminalized, and you can and will be put in jail for saying certain things (one example is talking about WWII and the crimes of Hitler in a manner that is inconsistent with the official version of history).
There are many other examples . . . don't be too hard on the U.S. system . . .