I can assure you alcohol can make people very angry and violent. There are people in prison now for causing serious bodily harm and don't remember what they did because they were so drunk.
No actually, you can't, not from that evidence at least - just because someone was angry and violent while drunk doesn't mean the alcohol made them angry or violent - from knowing many violent drunks, they all had an angry, violent side while sober too. Alcohol just made them more likely to find it acceptable to act on it - that's what it does, it lower inhibitions and critical thinking skills, it a depressant , it's not a Mr Hyde potion altering personalities when you consume it. It's not going to make a pacifist violent. It usually takes years of overconsumption before there is enough damage to change personality.
Just because they can't remember means fuck all other than they drank enough for their brains to stop processing memories. Alcohol and many other drugs do that, as do many other things. Enough stress can do that.
It also doesn't change that people can be violent while high so the whole 'would you rather a violent alcoholic or sleepy pothead' is bullshit, which is what I was responding to. Neither automatically creates those moods.
It takes more than just getting drunk or high to make someone violent. It's not alcohol or pot that's responsible for that behaviour, it's the person taking it.