That claim is incorrect because it takes in to account only one very small segment of the people who saw the movie (only US, Fandango-based, in-theater viewings are counted). That is not indicative of the wider audience feedback.
You also point out the discrepancy between professional reviewers and audience score ("The audience says: 99% Popcornmeter - 500+ Verified Ratings -The critics say: 10% Tomatometer - 20 Reviews - be careful who you listen to") as a reason for Rotten Tomatoes being untrustworthy, but the Tomatometer and the Popcorn Meter (all audience, not just verified) are close together (10% vs 28%).
Just curious, do you believe this movie to be good? Have you seen it? Or is this just a kneejerk reaction to defend an awful movie where more than 50% of the budget went directly the person the documentary is about?