There are no moderators, but in a sense we are all moderators.
Anyone can flag, or countervote, or whatever you want to call it.
The effect of such a flag depends on the size of the wallet of the flagger/countervoter, and the percentage they set.
Flagging is for plagiarism, threats, and the like, and relatively recently it has also been used to express "disagreement with payout". Some apply these guidelines more loosely than others.