Being asked for "your papers" is hardly different from stop and frisk.
New York City elects its politicians. In police states, the citizenry has no say over its leaders...
Wrong. Many police states have the consent of the majority. Hitler won overwhelmingly in a general plebiscite, and was quite popular with the majority of Germans, while the minority was being exterminated.
Democracy is not mutually exclusive from tyranny, and most certainly no protector of the minority rights.
You have a very basic misunderstanding of what rights are. The concept of natural rights, as enumerated in the Constitution, protect people from tyranny, which in its most common form is instituted and enforced by the majority.
They're actually very different. Stop and frisk is generally carried out in high crime areas. New Yorkers can try to end stop-and-frisk and black and Hispanic race hustlers are in the process of mounting court challenges, in addition to getting City Council members to put up legislation banning the practice. Citizens in police states do not have the ability to influence police procedure and can in fact be imprisoned or executed for merely questioning police procedure.