I don't know if I really understand your argument. You're justifying this by comparing it to CCTVs and eyewitnesses, but there isn't really any expectation that CCTVs and eyewitnesses respect the privacy of bystanders or limits on reviewing CCTV data or receiving reports of crimes from eyewitnesses in most areas.

Which isn't to say that I think we should allow limitless collection but rather that, even while justifying it using CCTVs, you're still treating them differently. I'd wager that's because it is different.