As someone who's been working with Nix for around 6 months now, it seems pretty informed to me, all the points he mentions are things we've had to deal with as well. It's not a coincidence that we're moving away from Nix as fast as we can.
This sort of elitism does not help anyone. I think many people involved in the project (me included) want it to be as useful to as many people as possible. Let's listen to the problems that people have and try to address them.
(Of course, Nix and NixOS are not for every target audience.)