In most (Western) countries you have a right to privacy when there is a reasonable expectation to privacy. What you do on the public streets is presumably something you don't mind the people seeing.
What you are suggesting is analogous to yelling out a personal secret and then being mad that people "eavesdropped".
> What you do on the public streets is presumably something you don't mind the people seeing.
The law of certain countries disagree with your.
A simple example that applies to the Italian law and to almost all continental EU countries. You are allowed to take pictures of every public crowd, simple. BUT you are not allowed to share (display) those pictures if they contain elements that could lead to the identification of somebody who is "already known to the general public". [1] The definition of "already known to the general public" is very fuzzy.
In addition, you are going to be in trouble if you publish a photo a crowd where there are minors and the faces of those minors have not been blurred or authorized.
What you are suggesting is analogous to yelling out a personal secret and then being mad that people "eavesdropped".