That is a worrying attitude. Searching to prove that something isn't there, as opposed to searching to discover what is there, or whether a thing is there or not? The expectation is going to bias the result.There does not need to be something more to it.
Jubes explained in the 2nd episode of I Catch Killers with Dan Box that the huge 2018 forensic search (and all of the money spent on that) was conducted simply to show that William did not lose himself - or not lose himself anywhere within the vicinity of FGM's house/Benaroon Drive/Batar Creek Road/the forest trails. That he wasn't laying there previously undiscovered.
I am pretty sure that the 2018 forensic search was also done at the Coroner's request.
This is why I find it helpful to listen and read everything about this case. Because I learn things that the public has not realised before.
imo