Even if that was true, any definition of Turing completeness that includes JavaScript and excludes C is worse than useless in practice. It's useless for communication, it's useless for education, it's useless for reasoning about capabilities. There's simply no place for such a definition in a civilized society.
Turing machines themselves are a useless concept in our society. Since C is lower level and tied more to the physical hardware it makes sense that it is not Turing complete because Turing machines are not applicable to the real world. Computers do not work anything like an infinite tape. I've never seen a practical program have to implement a Turing machine.
