I think you might not get it. “Reasonable expectation of privacy” is a legal matter; most wholly developed as a “do state agents need a warrant for that?” test, with some secondary applications in “can I compel private actors to stop doing that?” testing.
The question of whether something is legal is more or less orthogonal to whether doing it makes you an asshole. It’s true that many methods of being an asshole by recording people in public for the amusement of the internet are quite legal; but that’s not the crux of this particular matter; which is a good ↔ evil alignment question, rather than a lawful ↔ chaotic one.
