As a hardcore C programmer and zealot myself... How in the hell can you be productive like that? C is a systems programming language, not an application programming language, let alone relevant to the levels of abstraction you'd want in game development.
That said, "I am dead" is a very real video game indeed... and his arguments are very sound. I also can't stand C++. I disagree with him on Java though. The core language of Java is actually super simple, like C.
I think the productivity question hinges on what you count as the language versus the ecosystem. Very few nontrivial games are written in "just C". They are written in C plus a large pile of bespoke libraries, code generators, asset pipelines, and domain-specific conventions. At that point C is basically a portable assembly language with a decent macro system, and the abstraction lives outside the language. That can work if you have strong architectural discipline and are willing to pay the upfront cost. Most teams are not.
I agree on C++ being the worst of both worlds for many people. You get abstraction, but also an enormous semantic surface area and footguns everywhere. Java is interesting because the core language is indeed small and boring in a good way, much closer to C than people admit. The productivity gains mostly come from the standard library, GC, and tooling rather than clever language features. For games, the real disagreement is usually about who controls allocation, lifetime, and performance cliffs, not syntax.