I've certainly had my share of frustrations when applying for jobs, but they've mostly been the inanity of requiring a resume to be submitted AND to fill out an extensive questionnaire that asks the exact same things on the resume.
There is also the problem of unprofessionalism in Human Resources personnel, not unlike a lot of realtors I've dealt with. When they are in need, they are all courtesy and charm, but the second they are not, they disappear, do not notify unsuccessful candidates, etc.
I skimmed the article and didn't find all the alleged offenses to be unfair. The applicant applying in her 60's resented being asked how many years she thought she had left to work. That's a completely relevant issue when hiring anyone who is obviously nearing the average retirement age. There isn't necessarily any suggestion of ageism, as one may be the most qualified candidate for the job, but the likelihood of having to rehire in the near future in a work impact for the hiring company. They have every right to attempt to hire and retain long-term employees. There may well be a long learning curve in some jobs too, so taking a year to learn and then leaving a year after that is a bad deal.
Another candidate resented having the interview rescheduled after she got there. Afterwards, she learned that the law firm did it as a test and that she failed. That's legitimate. If a highly professional service-oriented firm wants to screen for pique, patience, or deference, that's entirely within their right and is relevant to high-toned clients who may need and expect more accommodation. The firm may well have experienced problem hiring courteous and charming staff only to find the veil dropping soon after being hired. So, they intentionally stressed the candidate if only slightly. Maybe the senior partners have had problems with cheeky underlings who chafed at waiting or whatever.
A third complaint was being asked to crawl around and moo as a student, for a job where the interviewer thought being fun was important. If the indignity of that ruined it for the candidate, then that job indeed was not for the candidate, but that doesn't mean the hiring company did not have the right to value fun and creative in a job hire, even minimum wage. The article threw the minimum wage bit in as if it werer an added insult, whereas, it's much more likely the job dealt with youth, children, or recreation, so was either summer employment or the like, and is completely normal for students to make minimum wage, as they have no experience.
So, there are plenty of bad interviews, but I've interviewed since 1975 or so, and the only time I had a bad interview was with Raytheon in Albuquerque in about 2013 or so. I was employed and well paid, but was considering changing companies, and applied and was given the interview. When I showed, the Controller had forgotten his appointments and had not come in to work that day (yet?), and I waited until he came into work after his staff contacted him. The interview went well enough, but I think I didn't get the offer because I was a lot better paid in my then current job, and they wanted a highly experienced person for cheap. As they never had to disclose their planned salary, and I had to tell mine, I'll never know.
