The students are doing this based on a Halloween email.

Yale Daily News reports.

Students confront Christakis about Halloween email

Following a three-hour-long impromptu confrontation on Cross Campus with Yale College Dean Jonathan Holloway about the lack of administrative response to allegations of racial discrimination that surfaced this week, around 100 students gathered in the courtyard of Silliman College to confront Silliman Master Nicholas Christakis about a Friday email sent by his wife, Associate Master Erika Christakis.

A heated crowd of students encircled Nicholas Christakis after 3 p.m. and accused him of racism and insensitivity, with many in attendance demanding an apology for the email statement, which admonished the censure of Halloween costumes deemed culturally appropriating. They also criticized Erika Christakis’ behavior during an open forum hosted at the Afro-American Cultural House Wednesday night — in particular, her attempt to leave the room before speaking or answering questions directed toward her.

“I apologize for causing pain, but I am not sorry for the statement,” Nicholas Christakis told the crowd. “I stand behind free speech. I defend the right for people to speak their minds.”

The gathering quickly became tense and confrontational after his response. Several students screamed at Christakis and called him “disgusting.”