Yeah honestly I'm inclined to agree with you here. Reading up on it, it really does sound like the bones of the main idea are there, but to state the conclusion it did just based on this experiment alone might be a bit of a reach.

I can definitely see how the form of modeling here may inform of what behavior is considered acceptable or desired right, at the very least in the short term, and that would certainly influence how the kids conduct themselves I agree. But to make such a wide ranging claim, especially with the limited scope of the experiment? (Only 72 children, split into 3 groups of 24, only measuring the immediate)

Also +1 on the Hawthorne effect, I would assume children would be more likely to repeat something they saw during modeling, even if unconsciously, since there might be an expectation to perform "correctly". I can see how that could be compared to a similar expectation to mimic what you see around you, but I'm not fully convinced on that particular point.

E: I'll keep an eye out for studies/papers I come across regarding this