Fine, but it is completely false that C++ offers nothing useful for kernel coding. You can see, for example, SerenityOS kernel making good use of modern features.
Any feature useful for coding libraries is equally useful for kernel coding, because the overwhelming majority of kernel code is identical to what goes in libraries, and much of it is, explicitly, library code.
So it's not surprising to me that Torvalds is critical of languages that don't cater to his use case. Nor why he's less vocal about Rust. The allure of Rust is inbuilt support for multithreading, protection against data races, and an efficient memory management system.