Assigning a Karma cost to down votes

If you want to down vote other people's comments that should cost you a point. I love Hacker News as an information source but also find many of the discussions toxic + negative in the extreme. Unlike real life there doesn't seem to be a cost in reputation/points for being totally dedicated to negativity. That's not constructive, and I doubt this will get any attention... and if it does it will probably just get negative attention... but there you go. Anyone have anything constructive to say about this?