I explained why this could be the case earlier. You see someone messaging someone else, assume they are mafia, but you can't use that as evidence because it's practically cheating and poor form. So instead you have to either use an ability or scumhunt them down.
Well what he's positing (which I can somewhat understand) is that you seeing him messaging someone is the basis for your suspicion. Obviously you're bringing up some valid reasons for painting him as mafia now, but I think he's suggesting that you wouldn't have been suspicious (or as suspicious of him) in the first place had you not seen him messaging someone.
@Fynn: Nutty already admitted that he and TSoL are mafia.