All of these commenters seem genuinely offended by the demographic representations on the show but I'm here to tell you, it's awful because of the terrible writing, predictable humor, reliance on a laugh track to sell its "jokes" and it's overall just aimless and boring.
I'm with you. I'm not quite sure what elevated it beyond "yet-another-sitcom" in the eyes of so many people, but it really seemed like standard sit-com fare to me, the few times I watched it (terrible writing, predictable humor, etc).