You can't really blame someone for acting resilient when THEY'RE the one being victimized. In fact, I think it's kind of douchey to do so. Like they've taken him from his home and his family, and they're trying to kill him with trumped-up evidence, but he's an idiot and a jerk for not sitting up straight and behaving…

Would you have preferred it if no one raised the issue of blood on the hunting knife when Byers gave it to the filmmakers a day before his home was searched? Or if when he told blatantly contradictory stories on camera, they made no note of it? That would have been more irresponsible in my view.

Unless you're going to argue that these children died in some kind of freak accident, its obvious that blame belongs somewhere. The filmmakers shouldn't be faulted for trying to find the killer.