One bad apple spoils the bunch.

It's way worse than that. Appealing to emotion "the cops might stalk you" is textbook useful idiot behavior because it implicitly makes the argument that if there were proper controls and/or transparency and/or accountability (whatever that means) this stuff would be ok.

Everything the cops have gets abused to some extent. Of course surveillance dragnets are no exception. The real danger of these systems is what happens when it works as intended. These systems are bad on a fundamental level regardless of how well done the access controls are.