Either they figure the alcohol in their systems will kill it or they don't give a sh!t as long as they can party on.
It is “normalcy bias”.
This is such an unusual event—no one alive in the US has seen anything comparable in their lifetime (despite the “just the flu bro” denial stuff).
The public pronouncements of all officials have been so wishy washy, contradictory, and incoherent that it is perfectly understandable for the average college kid to think there is no there there.
All the talk about “elderly at risk” is _not_ helping.