system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] If Muggle studies has been an option at Hogwarts since the days of Voldemort, why doesn't Arthur Weasley know more about basic muggle things?
gpt
Just because a class is available doesn't mean it is taught accurately or that the one teaching it cares to teach it correctly. Or that there wasn't a ministry approved curriculum the teacher was required to follow. 

Of course, considering Arthur Weasley himself is head of the Muggle Affairs department of the ministry, the question could answer itself--a case the blind leading the blind.