You are not wrong: Amazon now agrees not to move data from EU servers... unless compelled by authorities. US authorities can force Amazon to open their data centres wide open, regardless of location, at any time under Patriot Act provisions. Before Snowden, this was considered a far-fetched scenario, unlikely to ever pan out in practice. We now know that it happens pretty much every day.

The Safe Harbour program is a weak attempt at saving face: as long as the Patriot Act exists, no US-based company will ever be able to comply with EU privacy laws as they stand. Being "compliant with Safe Harbour provisions" only means that they're making promises they won't be able to keep.