Williams-Thomas disagreed with the abduction theory. I assume that was because he thought the evidence didn't support it. SIL also found no evidence to support it. Why then do you reach different conclusions about them?
Why are you quoting SIL as an authority? He has made a number of mistakes in his blog .... and I have only skim read part of it. SIL has done some valuable research and taken some wonderful photos for which we must thank him, but he certainly is no authority.
Williams-Thomas might have been influenced by the Mccanns being made arquidos? And his possible misunderstanding of the dog alerts and what they did and did not mean? I think many of us misunderstood those until they were deeply researched (thanks to Ferryman, Carana and others) and we began realise how futile they were.
Amaral, a senior Police Officer certainly misunderstood them, and maybe influenced by him W-T accepted them at face value, not realising what little they showed ?
AIMO, of course, but SILS mistakes are facts