unless one can prove that there is something special about being on HN that makes a person intrinsically different than other consumers I don't think this is a reasonable conclusion. It may be that this can be proven but I would like to see the proof.
If someone posts on a crafting forum, complains about youtube being broken is the conclusion that they are not the customer that most companies are targeting?
or any number of other fora, I doubt the predictor of a single interest is enough to differentiate the person so significantly.