There are just enough edge cases that they need that ability. Laws change, and they need to update to account for that. Sometimes the previous policy was wrong and they can't work at all without adding something that should have been there all along.
Of course most of the time changes are not needed at all to get the job done, just to violate your privacy.
Of course most of the time changes are not needed at all to get the job done, just to violate your privacy.