For significant cases where rewards do not add (enough) value ...

I think here you are leaving the space where you are objectively trying to achieve something that cannot be objectified. The vocal criticism of those who complain about downvotes is a value that can be called the value of "conflict in existence".

If you were a cool rational being here, you could probably readily agree that the presence of conflict makes a great value contribution in the social space of communication. I usually compartmentalise my subjective judgement of what I consider not worthy of approval in such postings (complaining, bruised egos etc.). I can abstain from any vote, but simply comment.

But I see the overriding potential of such postings precisely in the fact that, as a rule, the engagement of the comments that then start are quite passable: To see conflicting views being debated with each other. This form of engagement can hardly be found anywhere else. I think that can be readily admitted.

Now, one can say pejoratively that no one needs such a thing when it comes to advancing the cause and would probably meet with approval, but just not totally. Those who open the barrel and criticise loudly may not be totally right, but they are not totally wrong either. On another level, however, I would argue that the obviousness of conflict in the public sphere deserves as much of a presence as the obviousness of non-conflict, triviality and superficiality.

I would find it a nice surprise to see such gouged by the usual downvoters, just as it would be surprising to see the usual upvoters criticise it.

However, as long as one pretends that there are two firm fronts and neither individual is willing to admit that he is nevertheless on both fronts, the demand for proof of the other's probity is rather hypocritical insofar as one's own probity cannot be clearly proven. Since neither can be proven nor not proven, the impulses to try to do so nevertheless have a rather paradoxical character. My interpretation of "What is of value?" would consider the naming of this paradox as valuable.