This LA times story states that the studio for Red Dawn changed the enemy China to North Korea to not offend the Chinese. Why would it matter? Because they know this film will under-perform and that need that international BO of China. If they execs knew that this film will make hundreds of millions on its opening weekend in the USA. The studio would not care about how China felt, but this move also has another reason. Recently there was a release of a Video game called Homefront. Now this game is about a future USA in 2027 that is invaded by a resurgent NK, the game goes into detail to explain this. The game was also written by John Milius the writer of Red Dawn.
So some exec saw the commercials for the game mentioning John Milius and thought, we need Chinese movie goers, and if we connect this movie with this game we can get their butts in seats as well.
All they are trying to do is Lessen the Blow for a film that will be released in a already crowded blockbuster movie season. The figure this game might also create some brand awareness for their film as well.