This is not a new observation. At least ten years ago I read multiple comments noting that trigger warnings run directly against our best understanding of how

This is not a new observation. At least ten years ago I read multiple comments noting that trigger warnings run directly against our best understanding of how to treat something like PTSD. (Some mix of exposure therapy and emphasising mindfulness skills to anticipate and preemptively deflect triggers when not hyperalert.) Basically, those well enough not to sent into a fit on the spot generally benefit from those uncomfortable reprocessings long-term. Those who find it too uncomfortable need the skills to excuse and calm themselves (such as stopping reading). And if they can't do that then they need a lot more help than a mere trigger warning is likely to provide.