What country are you in that it's ok to talk in movie theaters? It's still considered to be very rude in the states?

That's never been my observation, and I've lived in five states. I guess we'll have to agree to disagree.

Wagnerian opera/ spectacle style theater was the first popular instance of dimming lights on the audience during the production. This was enabled by the invention and improvement of gas lighting, which could easily be set to different levels with simple controls. This created a forced dynamic of focus on the piece. This practice became more and more popular in European theaters throughout the Romantic period (second have of the 19th century) and eventually became standard practice in the theatre of Realism and Naturalism in the 20th century.

In the United States, around the 1850s. Formerly, crowds were more likely to engage with the actors on stage and talk amongst themselves during a show. As theater became a more "refined" activity, social etiquette required patrons to remain silent during shows and distance themselves from the actors on stage. Historian John Kasson calls this mid-19th century phenomenon "Disciplining the Spectatorship" in his book Rudeness and Civility and ties in this trend with larger changes in social etiquette.