Boomer is only one of more than a half-dozen people profiled in the movie. The movie makes it very clear that he doesn't represent anybody but himself, not just by saying so, but by showing so many other furries who are nothing like him.
The movie doesn't portray him as a freak. By the end of it, the (sold-out!) audience full of non-furries at the screening I attended loved him.
You seem very convinced that your imaginary "average viewer" isn't going to understand this documentary you haven't seen. Assuming for the sake of conversation that you're right - that the "average viewer" is going to ignore the other 80% of this movie due to, I don't know, unfortunately-timed epileptic fits - why should anybody care?
You really don't know what you're talking about.
You seem very convinced that your imaginary "average viewer" isn't going to understand this documentary you haven't seen. Assuming for the sake of conversation that you're right - that the "average viewer" is going to ignore the other 80% of this movie due to, I don't know, unfortunately-timed epileptic fits - why should anybody care?