All of that said, despite his ignorance of the demands these users have, he's right that they represent a very small percentage of all computing done today, and the "middle" tier computer is getting hollowed out by people moving down to smaller devices.
I'm not sure there's anything insightful to this, though: this has been happening for over 10 years now. Worse, it's a re-play of the same trend from the 90's with high performance workstations moving from expensive enterprise-only systems to Intel, which itself is a re-play of the same trend with the intro of the PC in the 80's. Computing gets smaller, cheaper and (largely) slower -- by the standards of the stuff it's replacing, anyway.
Their machines are absolute monsters - and necessarily so. I don't know what kind of video editing he is talking about - but video editing is obscenely compute heavy if you are editing for 4k - which is what you have to do nowadays - and you need to do include composite graphics, effects and run color correction to be viewed, in real time (on the array of a dozen different monitors, displays and TVs of various sizes that are in your editing bay) without upfront rendering - which is what is expected. To be able to replay the same hugely complex portion of video 30 times in a row with zero lag after making a change that requires the entire thing to be re-rendered.
I can think of few single-station use-cases, in fact, that are more computationally heavy than commercial grade video editing. You've got dozens of gigabytes of source material which has to be parsed quickly, loaded into memory, modified, composited and rendered at 29.97 - and the lag between commands and playback has to be effectively zero if you don't want your editors to blow their own brains out.
Maybe he means people using iMovie.
He could have ended up with 16 cores and 128GB building around the E5-2670, which is dirt cheap on eBay and elsewhere these days. $500 for motherboard, both CPUs, and 128GB (granted, DDR3 and not DDR4 per his build): http://www.natex.us/product-p/intel-s2600cp2j-128gb.htm
Honestly, my second-biggest worry (after the specter of a much more intrusive kind of harassment, which has already started to happen, hooray!) with VR is people trying it on machines that were built to save a few bucks and being turned off by the nausea of not having the necessary perf characteristics to deliver.
This is more power than a typical desktop user would know what to do with, by a pretty large margin -absurd overkill for just running an office suite or video editing or gaming or whatever.
His "Great Beast of Malvern" custom computer (http://www.catb.org/esr/hardware.html) is under powered for high end gaming and doesn't meet Virtual Reality minimum specs (http://www.geforce.com/hardware/technology/vr/system-require...). It is fair to argue that gaming, and especially VR or 4K gaming is a niche market that isn't a relevant consideration in his arguments, but he does explicitly mention desktop computers as overkill for gaming.