There are three options when you disagree with something on on HN.

  It's Wrong.
  It's Correct, and you are mistaken.
  It's Correct, but poorly communicated.

IMO, the poorly communicated issue shows up far more than most people assume. I have seen several discussion between two experts go X, that's wrong Y, that's not true X(1)... then after 10 posts they end up agreeing that X ~= Y if Z.

PS: This is also far worse on the softer ends of hard science. Diet, Economics, Climate, Astronomy, and Evolution all suffer from studying complex things with limited ability to experiment.