To tell you the truth, I am not completely sure how the ignore list works, or even where it resides. Although, I think the idea of ignoring (and I assume that means you do not see their posts, or posts in quoted replies, nor receive messages from them) somebody just because you don't like what they say is immature, and contrary to the idea of a forum.
There are plenty of unpleasant individuals in the world, but ignoring them often means not falling for bait as opposed to avoidance. Politically, that would be disastrous
. The only reason I would suspect that the ignore list would be useful, would be if one was being persistently harassed through personal messages (or stalked on message boards) however, I would imagine that this would lead to the said individual being banned.