To your direct question, bad actors exist, cuz interests can be misaligned. If we protect ourselves from all bad actors we'll have absolute security and no liberty. And then eventually we will have no security.

US founding father is often quoted as saying those who are willing to give up Liberty for security will have neither. Freedom is the only stable state politically, without freedom somebody becomes oppressed, when people are oppressed countries become unstable.

To answer the more philosophical question, you need to moderate the privacy in your life versus the utility it provides. If you're taking care of an octogenarian relative who could have dementia, or is it a fall risk, you want to be able to monitor them, to know if they are in trouble. Hopefully this monitoring comes with informed consent. There are many times when we don't need privacy from everybody, we can let some people in.

In everyday life, our neighbors usually know a huge amount about our lives. That's why they can check in when the patterns change. Hey I didn't see Bob check the mail for a day. We should go see him and say hi. That's a demonstration of the lack of privacy.

I think the main issue is when it happens with uninterested third parties who simply use their surveillance capabilities to oppress people, maybe not oppressed today but build the machinery to oppress tomorrow. And that's the main issue