"Lifelong distortion" is a strong claim that hasn't been demonstrated. I wonder how much of this consternation for kids being present online is a generational thing. People from the generation where privacy was the default are reacting badly to the movement towards no privacy being the default. Of course, those from the old generation take it for granted that their way of living is the right way and the alternative is "distortion". I'm also from that generation and I cringe at how easily people destroy their own privacy. But I don't make the mistake of assuming this emotion has normative value. The world is moving to a social-media infused existence. Being a digital luddite isn't obviously the superior lifestyle. Preventing kids from making the most of it isn't obviously in their best interests.

I think their point is that you and many others are underestimating how bad a "normal" childhood can be.