my initial perception of downvoting was that it was used to express disagreement with the subject of a post

I think that was the intent.

I do leave comments when I downvote but it is rarely productive. I think if we onboarded people with the expectation they MAY get rewards after the payout period but it is not guaranteed until the post is paid out that would reduce a lot of the over reaction.

You are right that downvotes are a tool. It is literally a part of the protocol... but some users act like it is a magic button or something lol.

More people have started to use downvotes which is encouraging. More people using downvotes helps decentralize that function. That being said, I do not recommend people downvote either cause it gets weird sometimes. I get retaliatory downvotes a lot and that is not fun even if you are a whale. 😅