reveals that:

Brainiac and the BrainaicWiki are only accessible by Justice League Unlimited members, and are used for the purpose of storing information on suspected griefers, griefer groups, JLU friendly contacts, JLU friendly groups, chat logs, JLU meeting logs, and people and groups of interest to the JLU.

So it’s more of a group aide memoire than just a list of people they don’t like.