I don't completely agree with the reasoning, but it mainly came down to driver support, maintenance cost, and debugging tools.
Inktomi (YST) was acquired in 2003, later Overture (YSM) and both were linux shops. YST was the biggest property by far and we didn't have any kernel developers. We were doing just fine with stock debian, then stock RHEL. (I did a few very minor patches for 32-bit, like splitting user-space/kernel to 3.5/0.5G instead of 3/1G, and some caching improvements for /proc, but I wasn't a kernel developer). Linux just worked. Drivers were available and supported for the HW we needed. Oprofile, systemtap worked fine for the most part. We later hired one kernel developer to help Mail move to linux, but we always had more freebsd kernel developers.
For freebsd you needed to write the drivers and the tools. That took time and money. The community was also smaller and it was harder to hire people with experience. Acquisitions were running on linux too.
The decision was not easy. Y! already had great freebsd engineers. By announcing that linux would be the supported platform going forward it was a given that many of them wouldn't be happy and leave. Fortunately not all of them left. For example Peter W. still works there.
In any case I don't think there was really an alternative.
Note that Yahoo! was employing a few very bright freebsd kernel engineers but when the decision was announced that linux was the future many of them decided to leave. That made the path forward even clearer. It wasn't just a matter of integrating new acquisitions easier, and the fact that it was easier to hire people with linux experience than with freebsd experience. That was around 2008 IIRC. I left in 2010, and Rick less than a year later.
I got an offer but turned them down because their recruiter was so crazy aggressive it made me feel that Netflix would be a very unhappy place to work.
From what I've heard from ex-employees (one a recruiter) the hiring/salary/firing process there is not well organized. People often make more than managers or more senior employees and large layoffs every year for the 'bottom 10%' make for some weird social dynamics.
As much as I respect and admire their technical processes there I'm not convinced it's really a good place to work.
I've been a happy Netflix employee for over 4 years and have never experienced a 'large layoff' event. All the layoffs I've witnessed were not a surprise for the people affected.
Senior engineers usually make more money than their direct managers, but I fail to see how that's an issue.
I'm guessing RayVR met with Patty who left Netflix 2 years ago. My interview with her was different but I guess it would depend on your background and what she was trying to determine. In my case it was mostly to see if I was going to be a good cultural fit since I was at the time working for Yahoo which had a completely different culture. To me that was an entirely reasonable thing to do. Actually the whole interview process was great, and it was one of the major reasons I chose Netflix over other companies.
It's not a definitive treatise on psychopathy, just the adventures of the author as he dives into this fascinating world. Definitely worth getting it at this price.