Unidentified parties mine blocks all the time, so it's doubtful that blacklists sent to the well known pools would be effective. Are they just supposed to orphan mined blocks that contain blacklisted inputs or outputs? How can anyone reasonably be expected to comply with a demand to fork Bitcoin?

Surely any pool that adopted such a policy would lose most of their members pretty quick. Same for any pool that leaves money on the table by deliberately excluding valid, profitable transactions.