Okay but a) to deny is a verb, and b) categorically denied and categorically untrue are pretty much the same thing. Nobody says it's categorically hot today even when the temperature is in the 30s or 40s. In fact, nobody says that something is categorically true.
It's a fair question and it sounds like politician speak to me. Why can't they just say it's untrue. They just like using three words where two will do.
...........and if I hear that phrase 'hard working families' from one more politician I'll scream.....