That's probably what's in the authors mind, but not what's in the article. The author is not just suggesting that client side verification is bad in itself, but stating that position quite precisely.

"Why client-side verification is bad.."

(rather than the title you suggest)

"to my surprise discovered that it did client-side verification of the words"

(rather than "...that it didn't do server side verification")

However, in support of your position; in his opening paragraph, he does say "you can't rely on it to do authentication", rather than "you shouldn't use it to do authentication".