The front page of the site links to "Shapchat is Harming Children at an Industrial Scale" (https://www.afterbabel.com/p/industrial-scale-snapchat) so I'm pretty sure it's about all of them. And at an industrial scale!
Note both of those articles are by the same authors, one of whom is Jon Haidt, who is a well known researcher on the harms that cell phones and social media have caused children since the widespread uptake of smartphones, and the author of The Anxious Generation, https://en.wikipedia.org/wiki/The_Anxious_Generation