I think it would be interesting to see what people's reactions would be if the topic were, say, smoking pot and being high instead of being drunk.
Other than some guy you don't know coming up and babbling incoherently to you, and maybe puking on your shoes, I don't see a lot of reason to become hostile to people who are drunk. (Past experiences with abuse, ruined family members, alcoholism, ect... excluded.)
I mention drugs because the same level of preconception and hostility gets directed at them too.
Like I said, short of someone actually imposing on you while drunk (which I admit drunks are kind of wont to do), drunks just are and I think you're right to ask yourself why you feel such hostility toward them. And I'd start by asking yourself what them being drunk makes you believe about them, that they've given you no reason to believe. Because let's be honest. No one except drunks really likes a drunk. It's kind of an embarrassing state for most people to be in. Most people accept that. So in the times and places where being a drunk is acceptable (like at a party), where people are likely to be drinking, what honestly is there to be bothered by?
I mean, don't get me wrong. My mom likes to hit it pretty hard when she comes home for the day and I find it both difficult and kind of infuriating to have a conversation with her, because she misremembers things, is sure she didn't, forgets things we talked about an hour ago, slurs a little....yeah. No one likes that. But it doesn't make me hate getting drunk. It makes me dislike how she handles being drunk.