To some extent, you are all dancing around a classic problem that the literature people have fought with for a while. Lit people love to worry about whether the meaning of a given work has anything to do with the intention of its author. To gratuitously smash the entire discipline of postmodern philosophy into computer geek-speak: many expressions have unbound variables, and you can only evaluate the meaning of such expressions in a context where those variables have definitions. (Example: You don't know what "X+Y" really means until I've defined X, Y, and for that matter, +.) To some of these lit people, there is no true definition of these terms, and thus the whole equation become dependent on the context provided by the reader, and we can all experience it in our own way. Start applying that to literature, and then assume the position of all sorts of critical readers, and you can generate reams of publishable scholarship, so long as you can use long and inscrutable terms to describe common, everyday things.

Back to Garfield, a postmodernist approach would perhaps put Garfield on a pedestal as the empty vessel into which we can easily put ourselves without fear of being too tightly constrained by our pre-conceived notions of the poor cat. That Garfield's creator can get rich off of it is can likewise be interpreted however you want. There's no true good or evil. Just a man making a killing off of a formulaic comic strip.