Having reading through three-and-a-bit pages of this thread, I'm going to basically take a middle-ground by picking out the points from each side of the argument that I find the most relevant and sensible.
The Bechdel Test is not, and has never been, a test for sexism. However, the article is extremely misleading in that regard, including the title, and I can see how that would lead to a lot of the confusion displayed.
To weigh in on the correlation/causality arguments, I think that it comes back to the writing of the article again. I highly doubt that the fact that a film passed the Bechdel test had any significant impact on its box office success. I do think, however, that the test is very good at highlighting the discrepancies in representation in films. Even without the modifications to the test, given that the population is a pretty equal split between men and women, it would be expected that at some point over the course of a film, two female characters would have some dialogue that didn't revolve around a man. However, as has been shown time and time again, this is rarely the case. Does this mean that films that don't pass are sexist? No. It simply highlights the fact that women are fairly poorly represented in film.
The article is mostly meaningless fluff, as it is difficult to really draw anything from the fact that more films pass the Bechdel test and do well, other than 'Oh, that's a nice shift'. However, I am slightly saddened by the number of people who seem to think it a bad thing that this is the case. Greater representation is a good thing, I don't really see how that can be argued against.