The "reward pool" that everyone loves to crow about "protecting" with downvotes is comprised mostly of "below minimum payout" fractional upvotes from small accounts.
All of this fractional dust is collected and then redistributed to the top-earners (posts that make more that 20 steem get some of it, and posts that make 200 steem get the largest percentage of "the reward pool".
So, downvoting = steal from the poor to give to the rich.
RE: Interview with a Big-Fish