> He criticizes the language-oriented model (in comparison to languages that people are familiar with but that allow embedded Deals, like Lua or Ruby)

Oh, I whish ruby had a more formal way to switch to DSLs - I love ruby, but can't stand meta-heavy/DSL-heavy subsystems. The rspec test system is a prime example (saved to some small degree by its excellent and detailed documentation): https://rspec.info/