What is it about Dilbert that seems to attract the extremely strict grammar cops from all over? The comments throughout the entire archive are chock FULL of them! I mean, I get irritated when someone uses "their" for "they're," but these guys just take it to a whole new level. The grammar in Dilbert is fine, especially considering that this person is supposed to be TALKING, not WRITING.
Grammar is an ever-changing thing. English has evolved from a conglomeration of other languages over time, inheriting their words and inventing new usages. Look at the way Shakespeare wrote, and compare it to the grammar taught in schools today (the same grammar that obsessives like Red love to nit-pick about). Just accept the fact that a minor contraction like "we're all" is now perfectly acceptable in place of "we all are." If Dilbert made people speak with perfect grammar, it would lose all pretense of realism. And that's what makes it funny!
Some of the few things about grammar I remember being taught over fifty years ago were that one must not begin a sentence with "and" or "but", split an infinitive, or end a sentence with a preposition. I've since learned that none of that was true.