Half of that happens because people are rightly concerned with another real world problem: teachers pet.

When only one student participates it disincentives others in the same way, to address that problem of playing favorites a downvote should be much more welcomed purely to object to the payout, it's not that they are right at all, because we know that it's far more rewarding to vote some other post as counter to that teachers pet content than to downvote and subsequently remove value from that post. We cannot stop that from happening in the code, we cannot remove downvoting from the code, we can change it, we can inform people of exactly the consequences of their actions, we can even limit the payout of certain posts and allow others to have a larger portion of the reward pool, but we cannot remove it. I agree that downvoting for those reasons is destructive to the community, but I believe that because it is seen as a flag to begin with, and that because the downvote carries opposite but equal weight (maybe a formula could be used to limit the extent of a downvote) to an upvote it only adds to the destructive aspect.