I don't think drugs "make" people violent - this is actually a prohibitionist concept; that drugs steal people's free will and dictate their actions. There is countless literature on this - try Norman Zindberg "Drug, Set, Setting", or Jacob Sullum "Saying Yes" or ?? Watson "Out of it" for starters.
Being intoxicated mught influence our actions, but it doesn't cause them. For example, meth is associated with violence in some subcultures, and unprotected sex in others. It can't be "causing" both! Funnily enough, at least one study says that the people who have unprotected sex while on meth also have unprotected sex when not on meth - they just do it more on meth!
Maybe it would be fairer to say that any drug that reduces inhibitions makes it easier for people to do the things they really want to do anyway...