I completely agree with the for kids aspect of this movie. The simple plot and misunderstood villain were very suitable for a younger audience, along with the colorful and slapstick Boov.

This being said, I expected something much different from this film. The book it is based on, The True Meaning of Smekday, deals with more complex and mature themes, such as invasion and the destruction of culture. It is more of a satire than anything, but manages to bring up themes of family that are also in the movie. As in the case of the recycled Megamind joke you pointed out, there was much in the movie that took up time that could have been devoted to exploring the themes within the original book.

If any adult thought of the movie Home as simply for children, I highly recommend reading The True Meaning of Smekday to see what the movie left out.