Cults don't usually have kills. It's possible, but unusual.
You're misrepresenting what happened with Usopp.
First of all, we didn't know Usopp was the vig (if he even was) until after he died. You applying that knowledge retroactively to Oddjutsu is very biased, to put it mildly. Usopp got himself killed; he put the town in a position where we had no choice but to kill him. Usopp aroused more suspicious than nearly anyone else in the game, and he was allowed to live under the condition that he shoot whoever we chose. Usopp not only claimed to shoot at someone nobody told him to kill, he also conveniently had no proof of his attack. With what the town knew at the time, we had to kill Usopp. The only person to blame for that is Usopp. After he died, I remember that several people noticed inconsistencies or oddities in Usopp's role. I don't think Oddjutsu even started the death miller theory.
I think it's very suspicious that you are planting your vote and refusing to move it so early into the phase, especially when important information is still coming out.