Lets look at it another way. The McCanns said the shutters and window were open in their children's bedroom at 10pm on 3rd May 2007.
I can say that in my opinion it's possible that they were not open, as there was no corroberation by any of the witnesses present at the time. I cannot say it's a fact that they weren't open, because that's an accusation that they lied and I can't prove it so it's libellous.
Amaral is a public figure, the McCanns aren't. I think that has a bearing on what we can say about what they say.
Certainly, Amaral doesn't believe the McCanns in general, even though he seemed to accept that the window was open.
You say "I cannot say it's a fact that they weren't open" I would say anyone who claims to know what state the windows were in is lying for they weren't there. Only Kate can say, but we don't have to believe her just because she says so.
"anyone who claims to know what state the windows were in is lying for they weren't there" So the post could be deleted for being untruthful. Rather than being libellous.