Mudd puts on an act to disarm people. His "Leo Walsh" is just that. As is the "Harry Mudd" he presents to Kirk and others. The real Harry comes out when he's alone with his "cargo".
You're still not even in the ballpark. Harry doesn't gun down the women ruthlessly. You're trying to lump every single form of bad behavior into a single category, but my whole point is that there are very different kinds of bad behavior, and the kind of extreme, casual violence "Mudd" was shown performing in "Magic" was vastly different from anything he did in TOS. It's like the difference between Cesar Romero's Joker and the Dark Knight Returns Joker.