Downvotes are tiny upvotes for everyone else on the platform.

You use upvotes to use the influence you gain by your stake, downvotes are the same exact thing in the opposite direction. Not saying all downvotes are good but in general they allow stake holders to use their influence given to them by their stake to decide where rewards should go.

If they think something is underrewarded then upvote it, overrewarded downvote. Downvotes are not violence by nature, granted many do use them maliciously but they are mostly to balance rewards based on how much influence your stake awards you. Without them, we become whaleshares.