Not doing anything wrong legally perhaps, but it definitely goes against common social norms. Notice most people don't actually yell at him, but just ask him what he's doing and ask him (politely) to leave. It's only when he doesn't, that people get upset.
I guess he's just "exercising his liberties", but that doesn't make it elaborate. Unless pointing out that people don't like awkwardness is all of sudden an elaborate statement.
Beyond any notion of it being a protest against the concept of a surveillance society, it's actually quite an interesting social experiment.
The responses are fascinating. A lot of people quick to anger. Many more people who have some — I'm assuming, although I'm no expert on the law in the particular area — false impression that they cannot be filmed without their permission. An alarming number of people who are prepared to call 911 over such a trivial matter.