I'd love to know why you don't care.
1) Do you really not care if people watch everything you do? Would you live in a Big Brother type house where everything you do is recorded and shown to the public? That includes you showing, shitting, picking your nose, having sex, watching porn, every conversation you have etc.
And maybe you really don't give a fuck about that. I guess some people could stand naked in front of a crowd and shit themselves an not think twice about it.
But then on the other hand, there is one more thing to consider. What if the current government, or another one elected in the next 5 to 20 years is really evil? And let's say they are against the things you believe in, and they believe anyone who believes what you believe should suffer unimaginably? Or what if you like to complain about things? You post negative restaurant reviews Write angry letters in the newspaper, stuff like that. And this new government doesn't like complainers, because they don't want to be challenged. They could just look at all the stuff you have complained about in the past and decide you are too dangerous. So they arrest you (and your family, because why not?) and then they put you in a concentration camp. Where you and your family are worked to death. Starved to death. Beaten to death. Raped. Experimented on. Burned alive.
I know it's an extreme example, but things like this have happened before. Except now it's easier than ever for governments to round up the people they don't like, and to find out who the people they don't like are. And the less you care about privacy, the easier you make it for them.
Would you still say you don't care about privacy? Or do you just believe something like that would never happen, and so it's not important that we take steps to prevent a future government to do such things?