It's the asymmetry of time invested that gets me. You (the interviewee) are expected to put in your personal time preparing a hastily thought out and assigned example problem that usually has, in my experience, nothing to do with the position, on top of investing even more time talking to interviewers beyond that. The interviewers are already getting paid to do that on their side so you're suffering opportunity cost not being able to take other interviews that may be more relevant. It's just a completely whack system and all about the power imbalance. But then again, whack is describing this stupid industry more and more these days so I guess it fits.

Personally, I think the main post hits it right on.