well then it should be public... that anonymous BS is what kills it... that way, if someone leaves negative rep, they can get asked why...
i got some crazy personal negative rep, and found out who did it... i didn't rep him back... instead, when i see him, i will punch his face in until he stops screaming...
if you're man enough to leave negative rep, then you should be man enough to do it without the anonymous BS... if it was public, i will still give negative rep to them that deserve it... that way they know why i told them to eat a dck...