My experience with the psychological effects of trauma and triggers is only second-hand, not first-hand, but I feel I know enough about the topic to disagree strongly here.
First off, the article you linked only talks about ptsd, but I feel it doesn’t cover all the possible (and useful) trigger warnings; there’s trigger warnings for eating disorders, for instance, or even for specific fears. The point is, for all of those, they cover situations in which some people can be triggered, which specifically means they will end up in a situation where they will not be able to stop unwanted, harmful thoughts or behaviors from manifesting. And in those situations, they are really not able to stop the thought, sometimes for hours, and if they do (or when it stops) they feel exhausted and miserable and their day is ruined. So if you’re talking about games, you’re playing this game to chill on lunch break, and it catches you with a traumatic scene that triggers you, and then you can’t do anything but fighting harmful thoughts for the next hour; not cool. You don’t want to do that to your players.
Triggers are really bad, they arise because of problems that caused psychological harm and distress that your brain can’t process and deal with alone; working on them is a long, difficult (and costly) process, but it’s overall better for the person if they can do it. You probably agree with that, and hey, the people who have triggers probably agree with that too, cause nobody likes crippling pain. However, talking specifically about point #4 of your article here, evoking a traumatic subject, in conversation or media or your game, when there’s trigger/ptsd is not helpful at all for the person: it just sends them in the downward spiral for more hurt and it sucks. There’s no desentization or whatever; you hurt every time. And sorry, but suggesting it does in the generality you used here kinda feels like “get over it”, which is super, super not helpful (because in essence the conversation feels like “i don’t believe in trigger warnings” “but it hurts me!” “it’s better for you, you’ll be fine”. Broadly simplifying).
What the article really says, it’s that controlled exposure to triggers with a mental health professional can help - a HUGE difference. And it’s true, they do work - prolonged exposure therapy, and emdr (which is based on repetitive left-right motion to reconfigure the brain) are scientifically proven to be effective, and they’ve been used in warzones for examples with great effect. But those therapies work extremely progressively, chewing little by little tiny pieces and processing them. If you take example of a fear of spider, you start by thinking about a spider that’s miles away from you, being ok with it, then you get closer, then maybe you look at a child’s drawing or a plush toy, and then on progressively, until finally you’re ready after a long process to see a picture of a real spider, etc. It takes a long time, and every time you panic, it’s cause you pushed yourself too far, and you have to stop instantly, feel safe again, and start all over again. It’s a very different process from playing a/your game - and if you’re not there yet, playing a triggering game can undo a lot of progress, cause you couldn’t handle it and your fear is vivid again.
That’s why I feel it’s really unfair on this article’s part to relate emdr&al to triggers for classroom discussions: they are not controlled environments, they could cause harm, and there’s no comparison. (I don’t know if i should give a specific example here, cause trigger warning, but let’s just say a discussion in a room full of freshmen can feature some genuinely clueless statements and some heated words, which is not controlled and can hurt even if you overcame ptsd). Similarly, you are not going to make a game that helps with ptsd (there’s a mmo-like game like this, developed by psychologists, can’t remember what it was) so it’s only fair to warn people that they could be hurt.
And don’t think people will hold it against you or your game if there’s trigger warnings: it just means that they can’t/won’t enjoy your game and it’s best for both of you to not continue. They’ll be happy you did it, and thank you for it!
(Unnecessary culinary metaphor: advertise there’s peanuts in the salad so that people who are allergic don’t order it. If you didn’t warn them, they’re gonna blame you; if you did, they’ll avoid it and say “phew”)
Finally, i can’t help but point out that point #5 confuses correlation with causation, at least in the way it’s presented: could it be that people who see traumatic events as part of their identity maybe took them harder and felt worse and had to deal with them for years, whereas if you can shrug it off reasonably quick it doesn’t take that big of a part in your life and so you don’t see it as a big part of your identity? Instead of the reverse, like the article implies? (“It’s bad for you to have this as part of your identity” -> hey, maybe it was just really bad for them). Just saying.
Thanks for reading the long post!