A skim of the article shows that it was not written from the viewpoint of a parent having to calm a hysterical crying child after having watched the movie. GotF is an emotional gut-punch even for adults. Incredibly powerful film, but that means it has to be treated with care and respect. That doesn't mean it can't be shown to children, but anyone who does so needs to be prepared for the consequences.
(As for me, I was in grad school when I saw it. I'm glad I did, but I don't think I will ever be able to bring myself to watch it again.)
The second paragraph literally discusses creating a self care plan surrounding watching the movie. It links out to several studies by child psychologists and articles discussing watching scary/sad media with kids and how to do so. It shows examples of how kids are interacting with stories like this safely. It recommends showing kids things like this in safe environments so they don't suddenly come to you broken and scared when horrors are thrust upon them when they are alone or unsupervised.
As a kid, I was "trolled" with fake links that sent me to beheading videos online. Tons of folks I know watched 9/11 happen live in their classrooms. Hell, the post talks about how pictures and videos from Gaza keep showing up on feeds on Instagram and TikTok. The whole point is parents should do that work and teach kids these skills and that it's okay to ask for help if they run into an emotional brick wall BEFORE they hit the brick wall.
But this is why ya shouldn't skim! Read deeply! (P.S. I wrote the post, I'm also literally a parent. If that matters to you.)