The interview process provides very little information to both parties about each other. Both of you have to make a decision on what you know. It is entirely possible that walking away from such an interview would, in retrospect, be a mistake.
However, it's a hot market. For every company that sucks at interviews, there's a company that's good at it. Why put up with it? Why waste hours?
Once upon a time, I was interviewing at two companies. The first, was a great interview..the seasoned and experienced found/CEO got me excited and interested and really made me feel that they were equally excited and interested in having me on board. They asked smart questions, they had obviously spent time reading my blog and looking at my public profile.
At the other company, it was painful...for both of us. I felt..like a chore that had to be done...going through a checklist of increasingly irrelevant questions. You could challenge the question, but the answer was "we want to see how you work through problems"....which is silly...are you so lazy that you can't come up with relevant questions that do that? Plenty of other people have.
My point is that, like everything else, some companies are clearly 10x better at interviewing/hiring than others. And, again like everything else, the shitty companies/interviewers have no clue how shitty they are.
Surely that might say something about the individuals and companies as a whole? So, again, why put up with it?