ReCaptcha only requires one (1) out of two (2) words to be correct in the challenge.
It presents one known-by-the-system-word, and one not-known word. If you get the known word correct (the easier of the two to read) then it passes the challenge.
ReCaptcha then pools the answers for the second not-known word and after pooling thousands (or more) responses, then that word becomes "known" based on the average answers (and then that word is "digitized" and used by google maps, or ebooks, etc).
And for those wondering, I find it easiest to read captcha's by just looking at the letters by shape.
Going down the list in the article:
Again, it's important to note, you only have to get one of the two words correct to pass the challenge. So.. probably 99% of the above list would pass.
Edit in response to your edits
You've deleted your previous edit. Still, even with your current edit it is clear you are not actually reading the article. You say:
However, the author of the article explicitly states that he did this:
I decided to just guess the first word and hope “secretary” was the control. It wasn’t.
So the author correctly identified one of the two words (and makes the same identification as you did), but was still rejected because it was not the control word.
You obviously don't have an accurate understanding of ReCaptcha implementation, and you apparently are not reading the article with comprehension, despite claiming several times that you have.
I do (I've implemented them many times), but no point in arguing.
I must be the only person who finds the level of security a captcha provides worth the 1 to 2 seconds it takes to type in a Captcha. And if done properly, you should only have to type a captcha once per site.
Which is easier? Allow form spam on your site, or have a user type a captcha once the first time they visit and decide to post a comment or something? Captcha's have provided a tradeoff between inconvenience and protecting your site.
Also, you say that you have an accurate understanding of ReCaptcha implementation based on the qualification that you have "implemented them many times". ReCaptcha was created by Google, so unless you work for Google on the team that implemented ReCaptcha, it doesn't seem possible for you to have "implemented them [ReCaptcha] many times".
From the article, in the context of ReCaptcha, it seems like Google has stabbed itself in the face with the sword of data.
Google may think the data is telling it something, but what it's really managing to do is irritate legions of humans with terrible (borderline hostile in this case) UI/UX.
I do have to admit most of those are cases where both words are difficult or impossible. But we can at least assume that the easier of the two (the one not cut in half) is the control in most of those.
The article's largest complaint is not being able to read one (1) of the two (2) words in the captcha challenge.
I was pointing out, that this complaint is not valid since reCaptcha (where all of the article's screenshots are from) only requires one of the 2 words to be correct.
It’s important to note the way reCAPTCHA works. Each user (or bot) is presented with a control word, and a word unrecognized by OCR. This control word is already known to Google (who runs reCAPTCHA). If you get this first word right, it is assumed that you get the second word correct as well. So, in reality, you only need to guess the key word correctly.
The author explicitly addresses your point and if you looked at his examples, most are very difficult for both words. In many of his examples, the control word is distorted beyond reasonable recognition, and the new word is cut in half or worse.
The article does make this point.
After your 'edit' my comment makes no sense.
I don't want to spend more than a second or two working out what a captcha says - if it wasn't something I absolutely needed I'd probably have gone away long before the author's patience ran out.