Let's be real: Jeopardy has always attracted contestants that fall a bit higher on the socially awkward nerd spectrum than the norm (we're all pretty tuned into this phenomenon here at BB, n'est ce pas?) Have you heard some of the stories these people tell Alex about their lives in the introduction segment? Some of them are just painful, grasping-at-straws attempts to come up with something--and this is with the help of the staff beforehand. This hate on Arthur seems misplaced to me. He's a nerd with a bad haircut who's not concentrating on his facial expression because he got his game-face on. This could be said of countless former contestants, but 1) they didn't have a unique strategy and win big like Arthur, and 2) they were white.
Jeopardy is a conservative show. Advertising is always targeted to a show's audience, and Jeopardy's is all for old people stuff: Life Alert, life insurance, medicine--literally every ad. This is a show that hasn't changed, except for the set design, in 30 years. This is programming that is a rock for it's audience in a sea of modern tumult. Phones, lightbulbs, banking, and culture are all fundamentally different than 30 years ago, but not Jeopardy.
All the hate on Arthur is really just the audience saying "we fear change." That's the whole reason they watch the show in the first place. (Except me. I'm down, right guys? : P )