Long long life Chairman Mao

I was traveling in this air-conditioned vehicle to Phnom Penh. The Cambodians and we were occupying the back seats, the other 6 places were for a group of Chinese, who also just visited Angkor. I knew, because what else would you do in Siem Reap and because they were looking at their photos on the tablet.
They also listened to Chinese music, which was quite agreeable, only it was always some version of one girl singing a song in minor. It was a very nice ride, the Cambodian countryside wooshing by, very fast, all these cultures transported.
But then the wi-fi (sic!) fell out and the music stopped.
They started complaining (no wifi! no! wifi!) and the Cambodian girl joked: "if no wi-fi, you sleep".

One of them started to practice English from the tablet and the lady that seemed to be the center of everything, said loud and clear "long long life Chairman Mao". I was wondering if I should correct her, but they weren't laughing, or anything, it could have been either sarcastic or patriotic, I couldn't guess the cultural context. So I didn't.