Yes, I find this frustrating too! However, before I fully realized what JKR was like, I kind of thought it was perhaps good writing, because it was reminiscent of how it works in reality. In real world, not even most good people care eg. about slave labour around the world that is directly conected to the production of the goods they use. I had shimmers along my spine reading it, because it rang true to me. Well meaning people CAN be totally oblivious to other people's suffering, including me.