Because many people are ok with mass-survielince as long as long as it's used fairly. The problem they see with this tech isn't that it's going to create the kind of world we don't want to live in but that it unfairly targets minorities and/or the poors more than other people. They don't understand that it can never be fair because the institutions that run it can never be fair because there will always be out-groups because that's how human nature works and they will get disproportionately screwed unless we limit the ability of the majority to screw them.