If the software developers do not include domain experts the project will produce drek. No question about that. But, end-users are not necessary domain experts. Most users do not know how the automated processes of their software work, and could not tell you the requirements on a replacement. I have often gone into replace a manual system and rather than simply implementing the current user's process, have provided a solution that required 1/2 or less of the effort of the original manual system. So domain experts are always needed, but not end-users per se.
The other point is that he is promoting a different way of structuring software development, so "reality" is not so important to him. He wants to change that. The current processes that leave mediocre programmers in charge of what the software does, is not a good solution, so why defend it? I certainly know that sense of helplessness that drives that lament. Being in a job where you feel you have no abiilty to make things better is very frustrating. That is the death march he mentions as the current status quo in many organizations.