I agree with many people above me when they say that sci-fi can be adult oriented. How many shows have we had that have been sci-fi and not for kids. Outcasts, Battlestar Galactica, Firefly, Torchwood, Twilight Zone, The Outer Limits etcetera. None of those are really for kids, but they are sci-fi. Granted, none of them are animated, but I'm showing that sci-fi should not be a disqualification. In fact, sci-fi was, when it started out, the best way for writers to express very sensitive and controversial themes. Saying that is not for adults is completely asinine.
Really, what should constitute and "adult movie" is more of the theme rather than the surface thing. So, okay, Toy Story does seem childish, but some other animated movies, such as the Lion King, as previously mentioned, are very grown up in its themes.
The "for kids" movies, such as the Great Mouse Detective and most other Disney films are, yes, a bit childish in their presentation maybe, but it's dual-layered. However, others, such as Princess Mononoke should not be disqualified simply because they don't fit into your "realistic" view.
Am I long-windedly saying that all animated movies should be thought of as "adult movies?" Well, no, not really. I am saying the good ones have varying levels. But am I saying that your rules are right? Definitely not. The worst one on there is thinking that an adult movie has to be completely realistic.