The trolley problem was first formulated by Philippa Foot as a parody of the ridiculous ethical thought experiments developed by philosophers of the time. Its purpose was to cause the reader to observe that the thought experiment is a contrived scenario that will never occur (apparently, it serves that purpose in most untrained folks), and thus serves as an indictment of how divorced reasoning about ethics in philosophy had become from the real world of ethical decision-making.

I've never heard this before, and nothing I've read on the history or uses of the problem as a tool of psychological study suggest that this is the case. Where did you hear this?