I don't think you should feel bad that you get turned off by drinking. Being in university doesn't necessarily mean that you should drink after all. It shouldn't be like, you are in university; you drink.
Maybe whenever you think of drinking, you think of all the drunkards and how drinking affects peoples' lives in a bad way. I get turned off by drinking too. Everytime I see this guy--seems upright, perfectly fine; and he says he drinks, and the whole image of him gets twisted. It's like you just have this sudden thought of him drinking, dancing around with other girls and stuff like that. Drinking simply makes people...not who they are. It makes them seem like...just not very good. =/ The thing is, bear in mind that getting drunk is different to all sorts of people. Some people curse and swear and do funny things when they are drunk while others tend to just become tipsy and then sleep the whole day off. Some people like being drunk now and then, it relaxes them. It's good that he's telling you it, which means that he's not this huge drinker and he probably knows how to control his drinking, which, well, is healthy.
Maybe it's simply the fact that all he is, attractive, athletic, smart...it doesn't relate to drinking. You can't put him and drinking together and imagine what it is like for him to be drunk or something like that.
But you know that he does not get drunk everyday, he probably just drinks while hanging out with his friends and it's a pretty normal lifestyle so don't get too creeped out by it. After all, who knows, you may be doing it too. It's not necessarily unhealthy, nor does it necessarily give you bad habits, and I don't think anything is wrong, it's just some people feel more uncomfortable about it than others.
I suggest you might want to find out more about his drinking stuffies. By doing that, you can reassure yourself that he's not some drunkard and neither is what he's doing unhealthy.
Good luck.