The timing of it.
Given that the ad was released at the time the players were accused, it was perceived as tying racism to the incident. Geez, it wasn't that long ago -- don't you remember this ad being interpreted as the Group of 88 supporting the students and the university against the accused lacrosse players?
Back then the 88 didn't object to that characterization. Back then those 88 weren't saying, "No, no, no. That ad was not judging the players! They're innocent until proven guilty!"
Only NOW are they making these statements.
Right. the timing is the issue as well as the context. This ad accusses these boys because of the context inwhich it was written. And it was done publically, which is worse!