And I've never understood this mentality. I don't feel entitled to perpetual demand for the kind of labor my employer provides, and I'd feel completely rotten about encouraging such waste just so I can keep exactly the same job. Where do people come up with this worldview?

Go back a generation and the concept of life-long careers was much more common. I think it's that social expectations for Boomers and earlier was that they would have a particular career for life, and many from those generations feel affronted at the thought of having to give up on their existing career. Effectively they feel they've suffered a breach of the social contract.