A disclaimer stating that scams are not banned doesn't absolve the forum from responsibility of being a vehicle for fraud.
By that same logic, if your Bitcoin node relayed a fraudulent transaction it received it would be a vehicle for fraud, therefore it's safe to assume every Bitcoin user running a node is just as guilty as theymos as undoubtedly every Bitcoin node has relayed a fraudulent transaction.
Thankfully the law doesn't work that way and there are laws in place designed to protect website owners from the actions of their users, which is why craigslist's owners aren't in jail for the actions of people like the Craigslist Killer.
Yes, indeed. Exactly why Craigslist provides infomation to anyone requesting formally; either private/through a lawyer because they've been ripped off or by government LEO's trying to catch criminals...