Exactly. The problem for Knox and Sollecito is that there is so much evidence that even if it was all weak (and it isn't) just the number of items is sufficent to arrive at a high certainty of guilt because they are all independent events.

http://themurderofmeredithkercher.com/The_Evidence

That is a lot of evidence. Some items are so strong that they in isolation would be sufficent to reach the level of certainty required to convict and others are strong evidence but not enough. I count 24 items.