It’s interesting you say there is no negative version of zaps. I’m thinking about this thought in the context of a business.
If you like what a business provides you vote with your money by frequenting the business, and giving your money as you received value in return.
Sure you can pay them money for no reason but the incentive to do so is not strong, especially not to do so at scale.
Now negative zaps, aka taking value from a business. The incentives to do this regardless of the business/product/service received is high. There can be way more negative actors as there is actually a reward for doing this and no punishment for the one negative zapping to stop.
I think letting a business just die by voting with your money elsewhere is as honest to a negative zapping we can get.