Problem is its only malcontents who post. People who are content just crack on because politics and local government isn't that interesting.
Makes it look like everyone is a whinger and the country is about to collapse because all comments are heavily negative and often racist. Its poisonous because it makes it look like such views are very typical which in turn influences moderate people to think there are deeper problems than there really are.
The best social media / messageboard is the Sunderland messageboard. The reason is that everyone has an opinion about football and we're all engaged by it. Even those of us who are content have an opinion because football is interesting to us. Therefore opinions generally moderate and we challenge each other, which means discourse on the SMB is the same now as it was in 2002 - whereas twitter and facebook have entered the cesspit, the SMB goes strong. Love the SMB and the Sunderland public.