I think you always have to remember that it is basically illegal for Mr. Weasley to own books on the subject. His most constant enemy is Malfoy Sr... who has the Fudge on a shiny, shiny leash. Aurthur's job is policing muggle items that get enchanted... Ignoring his flying car... if he starts talking about things like he understands them thourghly... he is doomed to get fired. He has far too large a group of dependants to allow that. I always got the impression that Misuse of Muggle Artifacts is a new department. One created after Sirius enchanted his motorcycle. He mostly deals with *air quote* Pranks *air quote*... that are played by Malfoy's peers. It makes idiots consider the issue resolved, while letting it continue unabated. That department is all about cover ups not stopping the misuse in the first place. Wizards get small fines... Muggles get mind raped for the criminal act of not being magic users. There may be something about keeping secrets in there as well.
For all we know Aurther does actually knows this stuff... its just politically unviable for him to actually admi it... consider he spent months living out of the same house as Hermione and apparently never asked her any questions.
For all we know Aurther does actually knows this stuff... its just politically unviable for him to actually admi it... consider he spent months living out of the same house as Hermione and apparently never asked her any questions.