My XABF was verbally abusive at times. Sometimes he would pick a fight with me. I could always tell it was coming when he started with "May I ask you a question?" I knew that he was going to bring up some little thing I did and it didn't matter what I said in response, I was in for a full-on verbal assault. Usually this was over the phone and if I hung up, he would call me again, maybe apologize and then start lashing out at me all over again. Examples of my transgressions included: asking him not to put his well-used overnight bag on my white bedding, not allowing shoes on my (brand new, dark click-and-float hardwood) floors. He absolutely could not comprehend that shoes bring in dirt and tiny pebbles which 1) scratch flooring and 2) track in dirt and allergens which make me sick.
One night we got in an argument over something and he decided he was leaving my house. He stomped upstairs and then I heard something hit the floor. I was mad and shouted from downstairs, "Stop throwing things!" He got mad, stormed down the stairs and said, "You shut up or...." He didn't finish the sentence so I said, "Or what?" "Or I'll punch you in the face." I made him leave then and while he was getting his stuff together I stood there and stared at him from no closer than 10 feet. The whole time I was thanking goodness that because of my regular gym visits I felt fairly certain that I could out-sprint him for a brief minute. I'm sad and embarrassed to say that was not the end of our relationship.
So while I don't think all alcoholics are abusive, I do think that alcohol disinhibits people's behavior so that they act in ways that would not be socially permissible (including abuse).