Most of the points mentioned make it reasonable to use central servers, but why did they need to drop the p2p encryption? The only thing that seems related is

Most of the points mentioned make it reasonable to use central servers, but why did they need to drop the p2p encryption? The only thing that seems related is "and other nice features like spam filtering and malicious URL removal" which he briefly mentions, but I don't find it a good enough reason to drop encryption and make it possible to intercept communication. Seems like an awful tradeoff.