What do you call a person or action who provides information irrelevant to the subject? [closed]

That argument is called a "straw man fallacy" or sometimes a "straw man argument." If I were to do that to you, I'd make it seem like you said something you never said, something I could easily disprove, then I would proceed by doing so.

The word sophistry applies quite nicely;

NOUN (plural sophistries) [MASS NOUN] 1 The use of clever but false arguments, especially with the intention of deceiving: trying to argue that I had benefited in any way from the disaster was pure sophistry (OED)

However this does lack the connotation of under research or lack of evidence