I can see how mental illness can hurt others and be a major pain for them, definitely, but selfish? No, just no. Not unless you consider it selfish to have a heart condition or diabetes or any other physical condition. I could just as well claim that people who think mental illness is selfish are themselves selfish, as apparently they think only about the inconvenience to themselves rather than the pain suffered by the person who actually has the illness.

My wife doesn't like me when I'm in a bad place, and that's totally understandable, but it's not like it's a walk in the park for me either or like I choose to be that way. I've cancelled a lot of things at the last minute, including a wedding, and I feel really bad about that. But really, who gets the worse deal, the person who is bummed that someone cancelled on them, or the person who is going through such crippling depression that they just can't summon the energy to drag themselves out the door?

Maybe it's the fact that in mental illnesses like bipolar, a lot of it goes on in your head or behind closed doors, so people don't see that. They only see the superficial effects like the ones you listed, and then conclude that it's selfish without any kind of real understanding about what's going on.