Who Will Protect Children From Dangerously Exciting Cartoons?

This morning Nick Gillespie noted the recent Pediatrics study that found 4-year-olds  exposed to nine minutes of SpongeBob SquarePants performed significantly worse on cognitive tests than 4-year-olds who spent nine minutes drawing pictures or watching the less frenentic PBS cartoon Caillou. "Parents should be aware that fast-paced television shows could at least temporarily impair young children's executive function," the authors write. The practical significance of this short-term effect is unclear. (Nickelodeon, for its part, says SpongeBob is aimed at 6-to-11-year-olds, so testing it on 4-year-olds is inappropriate.) But I was struck by this sentence in the Associated Press story:

The results should be interpreted cautiously because of the study's small size, but the data seem robust and bolster the idea that media exposure is a public health issue, said Dr. Dimitri Christakis…a child development specialist at Seattle Children's Hospital who wrote an editorial accompanying the study.

In what sense does this study "bolster the idea that media exposure is a public health issue"? Watching SpongeBob did not harm the subjects' health. Even if it did, why would that be a public health issue, as opposed to a private health issue? The former label implies a rationale for government intervention, perhaps through regulations aimed at ensuring that TV shows watched by children are not too fun or exciting. Calling exposure to SpongeBob a "public health issue" is just a pseudoscientific, quasi-medical way of saying, "I do not trust people to raise their children the way I think they should."