I acknowledge that it's difficult to explain what might have happened if Eddie was right. That's no excuse, in my opinion, for casting aspersions on the integrity or job skills of the investigators.
I haven't used the word "incompetence", AFAIK.
However, I'm not sure what other term could cover failing to explore a variety of potentially innocent / irrelevant explanations.
To be fair, they didn't have any experience with such dogs... whereas police forces with such experience would presumably have a better idea of limitations.
If ever there was a "misunderstanding" over their abilities, potential for error, substances within their training parameters, etc., then they wouln't necessarily feel the need to explore irrelevant alternative explanations.
At the same time, this was arguably Grime's first solo venture. There is also the pro-PJ build-up in the media, which must have been a double-edged sword, IMO.
According to the hype, the brilliant PJ team led by Amaral was about to close in... how could it then back down? The Portuguese social researcher Helena Machado has written some interesting papers on the subect.
And that's more or less my conclusion over the Jersey fiasco and a few others I can think of.