You're describing the stereotype of a mean drunk. In reality, there's also the happy or the sentimental drunk. They might just laugh it off or smile big and hug the person bumping into them.
For sure, alcohol reduces inhibitions. If you're a naturally chip-on-the-shoulder kind of person, alcohol will turn you into a certified jerk. Alcohol can turn other kinds of people into lovable fools as well though.
I didn't think the bar was to describe something that was true for everyone. I suspect what I described is true for many, across many cultures. I've also seen people I would have characterized as mild-mannered act much differently with alcohol in them. I don't think it's just strictly amplifying existing traits.
For sure, alcohol reduces inhibitions. If you're a naturally chip-on-the-shoulder kind of person, alcohol will turn you into a certified jerk. Alcohol can turn other kinds of people into lovable fools as well though.