Drinking is not a sin at all, but willfully getting drunk, is. College students, not all of course, tended to party to relieve tension and stress after long periods of intense study. Naturally they want to do something fun. However, many tended to engage in drinking games, intentionally risking themselves and their friends to drunkenness. Some even test themselves to see just how much they can outdrink the other.
This is an act of disorderly conduct, taking things in excess, and adding risk to themselves and everyone else.
But let us not miss the point: the point is that though we hate the sin, we do not hate the sinner.