> At least it seems clear that "arsed" was not a typo for "asked".

Clear as day, Bill. The writer has obviously chosen this informal, and yes, crude usage to point out his annoyance at the lack of investigative diligence by would-be scientific writers who question the roots of 'Brownian motion'.
I doubt the writer makes a habit of using this kind of slang. It rounds the article off nicely though, eh.