OP may have been suggesting it's not actually a CAPTCHA in the first place, under the understanding that CAPTCHAs are at least nominally supposed to target some

OP may have been suggesting it's not actually a CAPTCHA in the first place, under the understanding that CAPTCHAs are at least nominally supposed to target something computers are bad at. Chess is even a particularly ironic implementation because it was one of the first traditionally human passtimes where computers excelled. A site can have a CAPTCHA that's so bad it's not actually a CAPTCHA even if no one bothers to attack it. My hidden forum could require a user to sum one thousand integers before seeing any posts. I probably wouldn't attract any spammers (because no one would join to read their spam), but that doesn't mean the so-called CAPTCHA is beyond reproach.