The issue misses a good rationale behind why this is being added. The only hint at the reason is this:

It is currently impossible to counter the profits someone earns by upvoting without causing unwanted side effects.

So if we think a post is earning too much, we can knock it down a peg or two. I can rationalise this as a response to complaints that posts with low quality content earning excessively high rewards.

What the issue really needs to explain is why posts are earning so much in the first place and why that's considered too much.

We all know that whales are the users with the most influence and are the reason such posts earn the high rewards they earn, so is this really some kind of control to keep whales in check?