I'm struggling to find a problem with Christakis' letter. She's not trying to set the parameters of what should be considered offensive, she's just saying that it should be students doing that among themselves (with people inevitably stepping the line every now and then), not the university administrators. Something one can obviously disagree on (I happen to think involvement of authorities in daily life is something that should be endlessly debated), but these students are acting like she invited the KKK over for tea.