The article says: "While we agree that the well-being of children is a crucial issue and that the impact of screen-based lifestyles demands serious investigation, the message that many parents will hear is that screens are inherently harmful.
This is simply not supported by solid research and evidence."
If an effect is so small that existing studies haven't measured it yet, then it's probably fine to ignore it even if future studies might find a very small effect.
> you only get to raise your kids once
> If the jury is out ... err on the side of caution
> as with all things, moderation is key
It's one thing when you use hand-wavy platitudes to guide your own parenting choices. The problem is that supposedly rational organizations (WHO, government bodies) use similar hand-waving platitudes in setting official recommendations and policies.