Yes, apparently in some places in America (I'm told not everywhere) it's acceptable to cheer or even clap during movies. In the places I know in Europe, this is seen as very rude and you're supposed to be fully quiet, or maybe whisper to your neighbor at most.
It's also similar in public transportation. American tourists are often quite loud while locals speak more quietly in buses, trams etc.
I have been living in Germany for over 20 years now, and never once have I seen somebody clap at a movie. I mean, it makes more sense to clap after your airplane lands, at least that will make the pilots and flight attendants feel good, but who are you clapping for in a cinema? The projectionist (who's probably not even there anymore?).
Having said that, there is a kind of "continuously showing movie" in Germany where the audience is very much encouraged to react during the film: there is a cinema in Munich that has been showing The Rocky Horror Picture Show continuously for over 40 years (not non-stop though), where people sing along, throw rice, dance etc.
Maybe it is the type of movie or whether it was a dubbed or orginal version of the movie (changes audience mix)? Definitely been in cinemas in Germany with clapping.
I'm an American, and have never understood why others cheer or clap in movies. There are neighborhoods where loud comments on the movie in progress are not unexpected for discouraged. On the other hand, it was in an upscale movie where the guy behind me wanted to narrate Ed Harris's Jackson Pollock movie--sotto voce, but far from inaudibly.
It's also similar in public transportation. American tourists are often quite loud while locals speak more quietly in buses, trams etc.