It's not that we denigrate him. It's that we don't believe him; since it's not credible. It makes no sense to crack the door without opening it, as he claims he did, and it is unrealistic that he failed to open it if he wanted to (and that ge cracked the door if he did not mean to break it down). It also makes little sense to put together an attempt to break the door and the fact that Knox downplayed the importance of the locked door: it's inconsistent; or to put it together with the fact that they had waited at less another 15 minutes before calling the police after Filomena told them to do so immediately: if they felt that opening the door was so urgent to the point of attempting to break it down, this is also inconsistent.
Utter, utter nonsense. And symptomatic of poor, biassed thinking.
An objective, rational thinker would make the following observation: what if Sollecito did not want to do material damage to the door or the frame? What if he didn't want to risk damaging the door/frame and the consequent financial penalties from the landlord, especially if it all turned out to be a false alarm?
If that were the case (and it seems entirely logical that it WAS the case), then the series of events and the observed outcome all become entirely plausible. Here's how it goes:
1) Sollecito and Knox are worried about Kercher's whereabouts - they don't know where she is, she's not answering her phones, and they worry about whether she might be inside her locked room.
2) Sollecito therefore tries to gain entry to her room. He tries to force the door, but in doing so, the frame starts to crack.
3) Sollecito thinks along the lines of:
"Woops. If I carry on like this, let alone use even more force, then I'm going to totally break the frame. If I do that, then Amanda will almost certainly incur the cost of repair, whereas if I stop now it will be a very cheap and easy repair. What's more, we don't know whether or not Meredith is actually in her room, let alone whether she's in any actual trouble, so it's simply not worth risking doing serious damage to the door frame purely on the chance that Meredith might be in the room and in need of our help. Therefore I'll stop before I do any more damage."
That's how a reasonable, rational, objective person might evaluate the situation as an entirely feasible possibility. In my view, only a partisan, biased poor thinker would reach the conclusion that
"it makes no sense to crack the door without opening it, as he claims he did, and it is unrealistic that he failed to open it if he wanted to and that he cracked the door if he did not mean to break it down".
Furthermore, poor thinking also leads to the bogus "reasoning" that Knox and Sollecito must have been frantically worried at that point, while they waited some time to call Romanelli. In fact, it's far, far more likely (you know, thinking in an objective, rational way) that Knox and Sollecito only had moderate concern at that point. And if that were the case, then it makes eminent sense that Sollecito would have abandoned his attempt to get the door open when he realised that he would have to totally break the frame in order to do so, and it also of course makes eminent sense that Knox and Sollecito took some time to call Romanelli. I think it's very highly likely that Knox's recollection of panic at this point is an (understandable)
ex post facto rationalisation on her part. I think that the actual
evidence points to the clear likelihood that Knox and Sollecito were certainly concerned, but nowhere near to the point of panic at that point.
And of course once the Postal Police turned up with the two phones, this was a material new factor that naturally turned prior concern into genuine panic and worry. That's why, in the light of this new information, it now became imperative to break open the door, whatever the cost in damage might be.