Just because it's legal doesn't mean it's right. If you knowingly take a picture of someone you know doesn't want you to and you don't give them a chance to avoid it, you're a fucking asshole.
If it happens by chance then that it on them. But to secretly do it with intent is absolutely an asshole move.
This is wrong. If you are in public, so long as it isn't a private space like a change room or a washroom, you have given complete consent to your picture being taken.
Like whenever you walk into Walmart, or any other store. When you go to a baseball game. If you are in public, you don't get to cry "foul" because your picture is taken. No one needs your consent, and you don't get to call them an asshole. If you are in public...you are in public. It is the way the world has always worked. Crying about it, and wearing masks, and calling people "assholes" doesn't change this.
