A few years ago, I interviewed at such a company. I left humility and empathy in my feedback to said company. The level of contempt I felt from the interviewers left me traumatized. I'm not joking.
I've ignored every potential job ad I have seen from said search and ads company ever since.
It's possible, that you've got unlucky with a first interviewer, who had a bad day. And than bad mood reverberated. It happens. It's a noisy process. Don't judge them to harshly. (I don't work for said company.)
my interviewers were mostly mid-age, i.e. around my age, and we had pretty nice time, relatively easy questions/exercises, talked stuff about current and future products/techs, etc. - overall pretty typical interview, and i kind of was surprised what all the talk about their interviews was about. (too bad the offer was a very low comp L5 - that left me traumatized :). I guess you get what you pay for - i.e. i suppose one should pass their signature tough interview with the young hot-shots to get a good offer :)
I've ignored every potential job ad I have seen from said search and ads company ever since.