Some interesting thoughts here on the differences between debates in course discussion boards and the "toxic" level of discussion in other social media.
I was intrigued by the suggestion that a syllabus statement affirming our commitment to Title IX can serve to deter potential perpetrators of assault or harassment, as well as to remind survivors (and their friends) of the resources available. Kenyon's Civil Rights Coordinator has provided four examples of potential syllabus language, so you can set the tone which fits your class best. (Hat tip to Laurie Finke for the link.)