I'm as upset as the next person when guidelines are knowingly set improperly and people die, but the documentary makes the WHO out to be murderers. As with any organization whose funding and respect comes from governments and organizations, the WHO doesn't have any real power to combat misinformation spread by their funders and they're wise not to start a conflict. They're playing the only part they can play and continue to exist; they don't really get to say what the facts are once their funders say something different. If this documentary makes you lose respect for the WHO, I'm with you, but don't assign them the responsibility.
Aside from that the journalism seems not that strong in that it's trying to make the situation seem more criminal. The journalist consistently presses the types of questions that are designed to make statements in front of the camera rather than seek information, and when she's declined more interviews, she makes a show of it as if secrets are being kept or people are being silenced. Some of the sources are good but too many for comfort seem obviously biased, e.g. fired WHO employees and members of protest groups. They also sprinkle in a healthy amount cheaply empathy-seeking footage of a blonde girl who isn't even connected to WHO mismanagement.