I often disagree with other posters here on HN - sometimes just to play devil's advocate and stimulate conversation around a certain point or points.

I've been down-voted just a few times for expressing my opinion when I present a well-reasoned, logical argument. (Unfortunately I've been down-voted many times trying to be funny or posting a comment that's taken in an offensive way). I think you'll find that having a debate or even just a conversation with more than one side being taken is often the best way to see the whole subject.