De facto evidence that HTML is a programming language is right here on the computer screen. Arguments premised on turning the ought's of should's into is's are collectively considered fallacious. The fallacy goes by a variety of names including "is-ought fallacy", "naturalistic fallacy" and "definist fallacy".

That Turing completeness is a property of some programming languages does not imply that all programming languages are Turing complete or that Turing completeness is an essential property of computing languages. The assumption that the extents of Turing Complete languages are identical to the extents of Programming Languages requires some evidence in support.

Programming languages for describing state machines need not be Turing Complete and their implicit avoidance of the Halting Problem make them useful in practice