If I'm interviewing you, it means that we already think you are worth talking to. I don't want to waste either my time or yours. If what I'm asking you to do makes you uncomfortable, TELL ME! I can think of the last two people I interviewed who gave me a series of immediate "I don't know..." answers to a bunch of questions. They're happily (I hope!) working here now because we changed the interviews to go down productive paths to find out what they do know instead of beating our heads against a wall!
In a given interview, sure, he's hoping that he can hire that person, but how many people get interviewed before the position is filled? I'm certain the average is much higher than one.
No matter how much anxiety he might have, he's doesn't have to worry about stuff like paying rent, keeping his car in working order, or feeding his family, because he already has a job.
Not really - some interviewers may not get that an interview goes both ways, but it really is very much symmetrical. For me at least an interview is the perfect chance to evaluate a company and until now I've declined about 3 job offers simply because I didn't like the conversations I've had with the people doing the interviewing.
New (inexperienced) hires are also more likely to feel the bottom side of asymmetry, which can counteract the effect for the youngest.
So yes it is, and no it isn't, depending on the candidate and on the company.
But the interview process is such a time suck (not to mention that you have to nick out on your regular job which you can only do so many times for a half a day before they get wise) that by the time you are walking into an office for an interview, you've already made a non-trivial commitment. You can only repeat it a handful of times (assuming you have another job or are otherwise professionally engaged) before it becomes a real burden.
Now, if you are unemployed and you have a substantial financial cushion or can pick up enough 'anytime/anyplace' freelance work, sure, interview with 5 companies a week, take your time and be picky. But how many job seekers are in such an ideal position?
You also believe that the power dynamics of an interview are different than the power dynamics of a company, as in an interview making a mistake can mean the difference between being hired and not. I don't disagree with you here, as ultimately making a mistake in an asymmetric negotiation at a company won't always get you fired. In this case, what I was providing a response to my parent comment, that if asymmetric negotiations are a problem for a person then a company will never work for them. These two things are not exactly the same, though I wouldn't fault someone for taking difficulty handling one to imply difficulty handling the other.