I love how dissenting opinions get downvoted like this on HN. Moskie was not hostile or otherwise in violation of the site guidelines; this is exactly the type of comment that should not be downvoted.
I'm curious what you think the exact purpose of clicking on an up or down arrow is supposed to express?
There is nothing in the guidelines or faq to actually say what the purpose is, and I could see an argument for "quality" being the criteria, but there's nothing wrong with using the arrow to express agreement or disagreement, from what I can see.
It may not be "wrong" per se, but it could easily have the unhappy result of making dissent invisible (or at least less visible). Unpopular opinions, if expressed honestly and well, ought to be encouraged.
