The hash table nature means any particular piece of information is hosted on a specific node or set of nodes.
An evildo-er can either DoS that node (which is someone's home PC, so very easy to DoS), or become that node by repeatedly joining the network until they end up by chance in that location.
All hashtable based systems have similar weaknesses. With no trusted nodes, and no way to stop an attacker pulling off a 51% type attack (making any voting system useless), it isn't really a solvable issue.
