First, let me say that this is an often overlooked, gem of a film. An absolutely brilliant piece of filmmaking by Jean-Marc Vallee and the entire crew and cast.
So, why have so many people not seen (let alone heard of) this film? In this case I think this has to do somewhat to it being 1) a (french) canadian production (i.e. not coming from Europe, Asia or the USA), 2) it is a film that superficially (plot-wise) might seem to primarily be about gay/lesbian subject matter 3) the title of the film, which, while pointing to some inside content of the movie, is not really the most captivating.
Let me say, the film is brilliant. Ultimately, the film is about growing up and the dynamic relationships within a family. I say this while thinking how even that description really doesn’t captivate the true essence of the film…. So let stop right here and just say, that it is an amazing film (with an amazing soundtrack) and I highly recommend it.