"a mean-spirited, totally insensitive attack"

If it wasn't defamatory, wasn't harassment, and wasn't hate speech ... it's perfectly legal speech, even if it offends people and/or hurts their feelings.  

In addition, Ms. Klein is both an adult, and a well-educated academic in her own right.  She doesn't need to call in the "Mommy" of this professor's institution to smack down his speech, she can engage in civil litigation, all by her lonesome, if she feels that Mr. Potter's speech crossed a legal line and wants redress.