> “Trigger warning” was originally intended to warn about descriptions that could literally trigger a dissociative episode for people suffering from PTSD
To the extent it was, it was based on a completely misinformed idea of how triggering in PTSD works. In practice, if not in intent, it has been, from the beginning, an appropriation of the language of PTSD to serve as a vehicle for expressing personal value judgements and content preferences that have nothing to do with that. And there is research, IIRC, that it is actually counterproductive, inducing stress without helping anyone avoid PTSD triggering.
I don't think you know what you are talking about. The original use of "trigger warning" was very specifically intended for use on graphic material that could trigger a dissociative episode, for example an explicit description of child abuse or rape.
The phenomenon you are referring to - appropriating the language of PTSD for concerns of politics, taste or personal offence - is exactly why some people advocate replacing "trigger warning" with "content warning" or similar (and not because of associations with gun violence, as OP asserted).
To the extent it was, it was based on a completely misinformed idea of how triggering in PTSD works. In practice, if not in intent, it has been, from the beginning, an appropriation of the language of PTSD to serve as a vehicle for expressing personal value judgements and content preferences that have nothing to do with that. And there is research, IIRC, that it is actually counterproductive, inducing stress without helping anyone avoid PTSD triggering.