It's not true that there's nothing else to do here. The drinking comes first, the excuses after. It's got more to do with the downtown bar scene and the Greek system than anything else.
I don't know if it's still true, but when I was younger, you had to study at UM. Most of the people I hung with would have done so where-ever they were, but even the less engaged students had a little less time for intoxication. That made for fewer, smaller, but more intense outbursts, in my experience.