[Northern Monkey]

Nope the 'so called proponents of free speech' got the phrase from the social justice warrior types who would put a 'trigger warning' before anything that they think might upset any of their brethren.Or would say things like 'I'm so triggered right now' if they come into contact with logic or an opposing ideology and are rightly mocked for it.
I say rightly because you are right about PTSD sufferers or some anxiety sufferers or victims of a violent crime who can have things which actually trigger their condition and that is not something to mock or find funny.What these SJW types did is turn 'triggered' into almost a dirty word by using it so casually and in the wrong context.