Blacklist Ineffective

While the blacklist feature may be working as intended, the way it was intended to work is insufficient. The current mechanism is one-way; it needs to be two-way. It does work in both directions as far as party invites go; the blacklisted person can neither invite, nor be invited. However, the blacklisted person can still see all your chat, the effect of which is that the blacklist is effectively counterproductive to its intended goal. The aggressor can continue with personal attacks, slander, and so forth to everyone consequence-free, because you just can't see it.
The blacklist should absolutely work in both directions.

Honestly, it should keep you from seeing their character, too, but that's asking too much.
I guess so is making people change offensive names, too, because the definition of offensive is too narrow, but that's another issue.

Ironic coming from you. You need your yelling privileges revoked.