It has to do with the acknowledgement of one's own role in causing the repetitive nature of these boards.
Agreed. Choosing to debate with someone shows you have at least some amount fo respect for them. If someone posts something simply to incite and enrage others, it makes more sense to completely ignore them. By engaging in debate with them, you lend some credence to their hate, and help to further it along.
That's why there are certain posters that I don't ever respond to - just a waste of time.
As far as reviving the forums, both religion and politics are great topics to talk about. Everyone has an opinion on them. The key is to keep it civil. Disagree with someone, explain why you think they're wrong / you're right, without resulting to insults.
Lastly, being that this is a UK forum, it would be interesting to see more topics on things specific to the UK. I've been able to learn some interesting facts by reading the dialog between various UKers, but unfortunately, it often devolves into anti-US sentiment, which detracts from the value of the conversation.