laundering money for drug dealers is not morally reprehensible in its own right (unless they are violent drug dealers);
Given the multiple pending murder-for-hire charges against Ulbricht, I don't think you can use "Silk Road is all about peace and love" as a get out clause here.
Shrem is on record as saying "Let me help you, BTCKing, avoid getting caught because I think Silk Road is cool". Not entirely surprising what the outcome was there ...