I would more call it well-adjusted, which I consider to be a subset of sanity. If you're a drug dealer, know you sell poison (pick the "really bad drug" of your choice), never use it yourself, are happy with the money and relative ease it takes to acquire it (a debatable point, I'm sure), and have no qualms letting people be responsible for their own actions, would that be considered sane by the definition above? I'd think not. You know your actions are harmful, and choose not to change them, and are not empathizing with your clients and their further harm that you facilitate. OTOH, I'd still consider them sane by conventional standards, just not very well-adjusted.
This is not to say that the above definition isn't a laudable standard to strive for, and people who meet it would be very easy to interact with.