Jonathan Haidt is a very thoughtful researcher and has been looking at this and related issues for a very long time. I think your dismissal is perhaps a bit too casual.
The emphasis is mine. What does that to do with any of this? University students aren't children and, agree or disagree with the result, they are the ones with agency there.
What's next, shout down politicians you don't agree with? That's not how democratical societies work.
The paradox of intolerance stems from the 1930s. When we stay there for a bit longer - do you think that the participants of the Kristallnacht considered themselves evil? No, they were brainwashed into thinking that they were righteous, fighting to save their country from corruption and evil brought upon it by ... their victims, who "had it coming".
"We are fighting for a just and important cause!" or "We are protecting the vulnerable!" means precisely nothing from the mouths of a mob. A mob is mostly a psychopathic entity that just seeks rationalizations for its outpouring of violence.
Looking from afar, US left/woke/whatever is nowhere close to objectively tolerant. Unless you use a very nuanced tolerance definition. It’s long past „live and let live".
(As to to who ultimately has agency in inviting/platforming/deplatforming/protesting/canceling speakers on US campuses, that's a very long-running story, can involve media, donors, boards of regents, not just the students etc. But yes, noone's compelling the students to attend and listen, and in any case they can speak in response.)
A 2020 article on "safetyism" as defined by Haidt and Lukianoff in their book, The Coddling of the American Mind: “Safetyism refers to a culture or belief system in which safety has become a sacred value, which means that people are unwilling to make trade-offs demanded by other practical and moral concerns.” : https://www.insidehighered.com/blogs/just-visiting/safetyism... . One incident commonly cited was the 2015 Yale Halloween costume matter: https://en.wikipedia.org/wiki/Nicholas_Christakis#Yale_Hallo...
I think you're quite aware there are severely different legal considerations on content access to under-13s, 13-17s, and over-18s, in most jurisdictions.
As for legal considerations, it doesn't appear to matter that much.
Most children online consume media and follow recommendations, ads and friend feeds, rather than intentionally searching for topics in a structured and coherent way. Doomscrolling, bingeing, mindless zombie mode, whatever. We may not like it but you're aware that's the way it actually is.
As for legal considerations, it does matter: they define/limit the ability of YT, FB, TT et al. to build a profile and blend recommendations, ads and organic content. More so for under-18s and under-13s, more so where there are privacy laws (GDPR). If the US actually passed meaningful privacy laws this would have more effect.
Furthermore, Haidt struggles to accurately represent his ideological adversaries. Another red flag. Disagreement is natural but public intellectuals should be able to effortlessly make a strong case for the positions they have themselves rejected.
The more I see of these snide attacks, the less I believe there's any veracity at all in their belief system, which now spans an entire constellation of fringe politics turned mainstream.