In business, when we negotiate an agreement with a business partner, if it is sufficently-sized, we (our lawyers) may include all manner of protections against potential liabilities or losses resulting from the conduct of either party. This does not mean that each party expects the other not to perform as agreed. Rather, it gives us assurance that if something does go wrong, each party has its interests protected, as negotiated and immortalised in the agreement.
Having privacy laws is just the "right thing to do". It is a matter of mutual respect. Even if no one is doing anything "wrong". We still need those protections.
"Gentlemen do not read each others' mail."
https://en.wikipedia.org/wiki/Black_Chamber
This idea had to come from somwhere. Perhaps the ethics are part of the human psyche. However, history shows the only way to see the idea realised is to have laws that enshrine it. Without rules, some people will, in fact, read each others mail. And no one will complain about it because there is nothing they can do.
Privacy laws are good for society. They represent our best interests and our sense of what is "right".
Just an opinion.