For me, I don't believe in the idea that alcohol brings out the truth that lies deep within, that we do what we truly want to do when drunk. I believe the opposite. Certainly for me.
In my personal experience, I did the opposite. I flirted with women I had no interest in whatsoever. I said things that made no sense whatsoever to myself the next day (because of blackouts, I would need to get reports sometimes). I would break my own moral rules left and right. And denial came sweeping in to explain away any and all of my behavior. My excessive judgment of others was often simply a reflection of how I felt about myself - a projection of my attitude about life in general. I was often confused about how I was feeling inside, but ALL-SO-CERTAIN about what was going on outside in the world around me.
With that being said, I was still responsible for everything that happened while drinking. If I said something inappropriate, then I'm responsible. If I did something inappropriate, then I'm responsible. I have the sober me to look at the drunk, thinking, damn it dude - I have to clean up your mess. But it's my mess. I work to accept that I am a human that makes mistakes.
This is how I view my alcoholic loved one that is still active. He is sick. Very sick. In his sickness, he says things that make no sense. They're ridiculous. They're abusive. Yes, it's true, that with sobriety, he may still cling to the same attitude - that drinking is not the only path to abusive behavior (lieing, cheating, stealing, etc). That a lack of drinking will not automatically heal our relationship - that even sobriety might not bring that about. He would likely change dramatically, and I might find myself missing the old dad. I don't know, because I haven't experienced it.
There was a time while I was away for school and my father was raising his grandkid. I returned to visit for a holiday and observed him as being completely different. A gentle, more relaxed, funnier kind of version of him. He had made an effort to stop drinking hard-liquor (no more scotch, but drank beer still) - I guess he was trying to change for the grandkid? Funny thing was several of my brothers complained that he was soft - or wimpy or was spoiling my niece. For me, I thought that the real father. the real person - the healthy version of him. Was coming out. Not fully - but definitely a significant change. However, due to my denial of his disease at that time, I said just about nothing about it. Pawned it off as him trying to be a granddad.
With that said, each human is different. Some people may not change at all when sober. You may experience the change and say, hmmm...still an a-hole. For others, you may like the sober version of your loved one much better. In my opinion, they're still the same person - it can simply be a dramatic change between the active alcoholic version and the sober version of them. For me, I love my changes and feel better about myself. Some people have told me how much easier it is to be around me. Other people, don't like the change - I'm not as easy to push around because I have boundaries now (my active alcoholic loved ones).
I definitely said some things I truly did not believe - that my purpose was to simply be mean. That I didn't know how to express anger - so I would blurt out something nasty to express it.
It is true that if you take away the booze, the person may continue to say the same thing. They meant it before, and they mean it after. There's also a case where the person is so sick that they are NOT saying what they mean. Instead of thinking about whether it's the booze talking or not, I just think to myself...that sometimes. Their nasty comments, aren't about me at all. It's about them. and I try to accept what is and leave them to their negative attitude.
My two cents.