If the film is average to good? I can't see how that's the case. How do you make an average to good final product look like trash to the point that it rakes in bad word of mouth, an amazing amount of dislikes on youtube, and making a ton of people turn their backs away going "what the hell?" Yeah, there was some controversy around Star Wars (I personally saw that there as being more at a corporate level (like merchandising companies not getting with the program), but might not be remembering that much) - but it didn't rake in dislikes like this film did so there was more at play than "all those dislikes were due to sexism." Many? I can see that, but not to the point it got to.
You even said you hardly laughed at any jokes in the trailer - of a comedy movie. If it is average to good, that means it has some average to good jokes in it - those should have been used over the ones that fell flat. We have had one member in here who has seen the film puzzled even over why they chose the jokes they did when the film according to that poster had ones that were a heck of a lot more funny.
If they had an average to good film to promote, there should be an average to good way to promote it - not making it out to look like a train wreck. As you said, all they had to work with was what they had - here that means all they had to work with was something that may be average to good.