I don't worry about it being changes to the source material but I share your reaction here, in that a lot of movies today seem to over prioritize the political and social message, often to the detriment of the story and characters (nothing wrong with political or socially conscious movies, but it becomes the primary goal, and when it is done in ways that feel reductive or humorless, I tend to get annoyed). And a lot of changes feel forced for that reason/ Also something about the way they do this, just doesn't land well with me a lot. I think there is a disingenuousness about it that bugs me (like they aren't making the movie they want but are making a movie that will safely navigate online conversations). That said, I wouldn't want to take that annoyance and extend it to create a general rule that changes to source material are a bad thing. I want filmmakers to use novels as a springboard, not just a paint by numbers adaptation. I also wouldn't want to take that as a general rule that messaging in movies is bad. I do want an honest movie. This is one of the reasons I like Starship Trooper's handling. It does have a heavy handed political message. But it was his honest reaction to the source material and it has an edge and humor to it that is entertaining (also he was honest about not finishing the book, which I respect given how sacrosanct finishing books are in science fiction fandom). It is also a reason why I liked Starship Troopers, Heinlein was presenting his worldview honestly.