I think the explosive reactions by people who think the next enemy of freedom of speech are survivors of PTSD is both convenient and telling. Triggers are behavioural associations and are thus individual and impossible to predict with complete accuracy—but for topics like rape, child abuse and assault, it is easy to make an educated guess. Trigger warnings aren't mandatory, and they don't change any content. They are a courtesy, indicating compassionate human beings who want to do something easy to spare someone's day becoming dysfunctional. They are not about you, unless you want to make them so.
—WWSD