all "facts" are useless by definition

[Busty Doll]

That said, if someone literally means:
"Every fact is useless by definition,"
then yes, that statement is almost certainly false. Plenty of facts are obviously useful—engineering facts, medical facts, legal facts, and so on. Unless they redefine "fact" in some unusual technical sense, the claim doesn't survive ordinary scrutiny.
As for the person posting it, I wouldn't put a numerical "stupidity" score on them. It's more accurate to say the rebuttal is overconfident and somewhat performative.

Yeah he means a bare fact is not useful in and of itself. It needs to be followed up with the an explicit Step 2: Putting the fact into Usefulness.