I don’t think pot makes people violent, any more than it makes them passive. I think it makes them easily manipulated, into being “flower children” or assassins... or sex objects. Whatever the manipulator wants. Manipulation is easier with pot.
If you read the online pot shop descriptions of varieties they carry, the Indica- and Sativa- based strains have pretty much opposite effects (but none inducing violence). It seems reasonable, though, to infer that too much sativa in a violence-prone personality could have energizing effects including violent behavior.
My extensive research on assassins indicates most drank beer and didn’t smoke.
But I defer to your expertise.