If a movie can't get made, it can't get seen. Certain subjects and themes are taboo in big Hollywood movies, for instance anything anti-communist, anything even mildly critical of the "gay" lifestyle, anything "flag waving", pretty much anything pro-business, etc.
One common theme is to initially portray protesters or environmentalists as the villain but then as the movie progresses, it becomes clear that a greedy corporation is really to blame.
I can't even count how many times Law and Order has used this. This occurred recently on the show Numbe3s, where a unabomber type guy was originally the villain but later it became clear that he was just trying to expose an drug company that had illegal allowed harmful drugs to get to market.
Another popular one is to show lumberjacks being injured by spikes being put in trees by protesters. Initially law enforcement goes after the misguided, but well intentioned youth, but as the the show progresses, it becomes clear that the lumber company is actually doing something highly illegal. The corporate boss that makes the initial complaint against the protesters is always the one that ends up going to jail in the end.