Are they though? The fact is that almost everyone on earth knows the difference between men and women. Only young children are ambiguous (when clothed). As early as 8 or 9 years old most children's face shape starts to take on features of their sex. To the point that even when identically dressed, a girl with short hair or a boy with long hair can still often be correctly identified as male or female, when they'd have been ambiguous a year or two before.
We all know what a woman is and the vast majority of people are either unaware or quietly pissed off at what is happening. Anyone who watched this movie is already pissed off or was unaware and got pissed off when they saw it.
And while Matt Walsh is controversial for lots of reasons. (I very strongly disagree with a lot of what Walsh stands for. A lot.) I actually find him to be kind of likeable in how he comes across on video. I've watched some of his youtube videos on various things and I think he's occasionally witty, a good presenter and gets information across in an informative and entertaining way. He comes across as someone I would like to have a chat with, even if outside of our similar opinions on gender ideology, we disagreed on absolutely everything else. So I honestly don't find it surprising that his documentary is so well rated as he's stating the obvious, in a well put together way that almost everyone on earth is actually, deep down in agreement with.