I think a large part of a problem of this sort comes from simple ignorance - here's a great
anecdote about one man's actual feelings and interactions with someone in blackface (even if I don't agree with some of the general conclusions drawn, it's still a good perspective).
Honestly, we'll never know if the guys at UT came with ill intent, dressing in blackface specifically in the minstrel tradition, if they had previous understanding of the impact and feelings of this tradition, or if they knew who Al Jolson was.
Obviously, if they didn't have this understading and showed up wearing shoe polish simply to round out their costumes, it doesn't lessen the impact on those students who they came into contact with - the racial insensitivity remains. However, if this intentional ill-intent was not harbored, I find it to be another sad example of just how little we understand each other on a basic level. I don't know if that makes it better, or worse.