I can see how this thing about protect one community forum could seem a fantastic world of power, decisions and choices...
And i can understand that everyone has a better solution for the world's problems while having a beer in the bar with his friends..

Here a few words to explain the points of the situation:
0 - Your are debating about a report without any relevant information (which is the ip address of the exit point? If it was reported everyone could cross check if there is a clear reason or not for the block)
1 - blacklist is not composed using human choices
2 - blacklist is composed merging more automatic malicious reporting sources
3 - there is no will to block tor exit nodes or common privacy proxies
4 - if one tor exit node has been reported in those reporting systems i think it would be a non-sense to add it in a white list giving them a different priority
4bis - if your privacy proxy has been reported for bad activity why should we take care of it if you don't care to apperar just like a spammer?
5 - blacklist could become more aggressive during an evidence of attack (like it happened some month ago) to block the subnets used by attackers since reporting systems are slow and before a new ip in the same subnet is listed there it could take 6/12 hours. Normal behavior is more relaxed
6 - often those attacks activity is not limited in posting and create new threads, but also in trying any possible attack against vbb/apache/php and the point is not only take care of spam posts
7 - if it wasn't clear, our human resources are not unlimited and we have to make _real_ choices to reach a good security level without forgetting the man power involved.