Wouldn't nerving downvotes/dislikes make it harder to voice your option freely? It's the easiest way to signal if you dislike something (And ofc the other way around with upvotes). But if you make it harder to do that, you'll suddenly have a lot of people that just don't bother. That will create a false sense of acceptance of whatever has been said and will make it easier to create echo chambers.
We've got something similar. The fork we have came in a pack of two. The one we don't use for cat food is in the drawer with all the other forks and nobody ever uses it.
Couldn't that be said about upvotes as well?
Also: Nobody owes anyone anything and that also goes for explainations on up- or downvotes.