On the Media did an interview a while back with Cornell professor Kate Manne discussing the positive aspects of trigger warnings: 
KATE MANNE:  Mm, I mean, the reason I give trigger warnings is I'm teaching material that traditionally people have been protected from in the academy. There is very little discussion, say, of misogyny and sexual assault in Philosophy until feminist philosophers began to introduce those topics. So it's not obvious to me that this is really about coddling, so much as that's an expression of resentment to extending basic consideration and kindness to people when, in fact, new and more challenging topics are under discussion.

BROOKE GLADSTONE:  The weird thing is that the banner of academic freedom has been picked up by both sides of this discussion.

KATE MANNE:  Yeah.

BROOKE GLADSTONE:  What I see is the creation of an environment where it is the professors that are being curtailed in their speech.

KATE MANNE:  Yeah, I mean, I think a lot of people who historically have been very privileged are feeling unfree because members of historically subordinated groups are freer to morally criticize their statements.
I haven't encountered trigger warnings in real life, so I have mixed feelings.  But like any issue these days, most people have simply followed the lead of their political party to determine their stance without actually thinking about it.  This interview presented a pretty rational viewpoint. #psychology