The reason that this sets him apart from John and Elly can best be explained by these two seemingly unrelated strips. In both instances, John is trying to do what he assumes to be a favor and in both instances, the beneficiary of his flat-footed, wrong-headed generosity reveals what she thinks is going to happen via a thought-bubbled image. While I do realize that we're meant to shake our heads and chuckle ruefully at the crazy ideas overly dramatic teenagers come up with, it seems obvious as all Hell that the Patterson children wouldn't believe crazy things if their parents were in the habit of actually speaking to them as if their having an opinion that varied from their own or wanting to not do something that is less about themselves and more about their parents' need to live vicariously through them weren't some sort of crime.
This means that the reason that Elly simply will not listen to Michael about his feelings as if he's having the fun sucked out of his life for no reason is that she doesn't and never has seen Michael (or, for that matter, any of her children) as a person in his own right with hopes, fears and interests that must be respected. Elly sees him as simply an extension of herself, placed on this Earth to serve her needs and her needs alone. Since his giving up the trumpet to find something he liked to do better means that she cannot bask in his glory or be praised for not doing a Hell of a lot, having to listen to him about how he feels like he's being tormented so that other people can live their lives through him is not something she's willing to do. Sure, she might worry about his feelings once in a while but only in private and it never affects how she behaves.
John, on the other hand, makes being an unyielding rock colossus of insensitivity into a virtue so the idea that the people around him might want to do things that he doesn't blindsides and angers him again and again. In his mind, Mike made a promise so he better not welch on it.