My first thought was also "show-dead"; my second thought was a "comment cost".
Klocs are silly because they represent cost rather than value, correct? So perhaps comments should start out with (-1) karma rather than (0). That way, people will think twice about posting snark.
Otherwise, new users are unable to judge for themselves whether they agree with how the community endorses comments*.
Without such options any community eventually becomes a self-perputating hivemind.