I don't believe it's any more childish than ROTJ. I think there's a certain kind of fan who will say that any OT film is better than the prequels simply by dint of the fact that others still had a say in the OT whilst the prequels exhibited total control by Lucas - and we all know how highly regarded he is by a lot of internet forum posters.

I don't believe Peter Jackson makes films for kids, though. From a child's point of view (if I may dare to be so bold) he makes films that are long and boring with quite a few frightening moments. King Kong? Dull as ditchwater until they land on the island. Then it's scary scenes with the natives (not at all child-friendly) and sub-par CGI dinosaurs. Lord Of The Rings? Again, for any kid (and even some adults) it has incredibly long sections where not much of interest really happens (a lot of talking and walking) and then scenes with Orcs that, as with the natives in King Kong, are terrifying for kids.

Pixar are amazing, though. I think we all have our favourites where they're concerned but mine would be Up.