It's interesting, the concept of academic freedom is supposed to prevent individual researchers from having to in any way pay service, even lip service, to anything not directly related to their research. It is a fundamental principle of academic research, and your comment reminds me that even if as you say, people are just putting down some platitude about broader impact, it completely flies in the face of academic traditions where researchers are free to judge what is important and what is not in their work. This kind of requirement is an end run around academic freedom which exists exactly to combat any outside influence in research