You're being silly and stating obvious things. Their past isn't one event. Everyone has made mistakes. But it's not just one mistake that determines everything. By the time someone gets to college they will have, on average, 18 years of a past. The more recent years will matter more. The bad things they've done depend on the severity. And it's not just the bad, but the good.
If I alone were making the decision on them, I would cut them hard if I even thought they'd present a risk to me because I don't want to see "Johnny McThug was caught snorting lines after beating up the dean because he didn't like the fact that he wore his former gang colors. Johnny McThug is also a member of...."
-Rudey