Agreed, the problem with any anonymized system which attracts lots of users is, it creates incentives for bad actors to game the system.

Feel free to think up all the rules you want to prevent this, but a motivated entity can always simply pay large numbers of people to act on their behalf. If they're good at it, you won't know until it's too late.

Past a certain point, involving people's actual identities in the nitty gritty real world becomes increasingly necessary to establish trust. There are exceptions, but AFAICT they mostly rely on being uninteresting to would-be attackers.