Here's why the film failed, in my opinion...
First off, let me just say, I have nothing against Daniel Radcliffe as an actor. In my younger days, I practically grew up watching the Harry Potter films. When I initially found out that he was going to star in a serious film, portraying an undercover agent who attempts to infiltrate a white supremacist group...I was intrigued. The trailer of the film certainly looked interesting.
But I was quickly let down. For whatever reason, I just couldn't take Radcliffe's character seriously. Maybe it's because I'm so used to Radcliffe portraying Harry Potter. But for whatever reason, something about his character was just unfitting and unconvincing at times. I mean, I gotta give Radcliffe some credit. For a poorly written script, he did the best he could. But still...it lacked substance and realism. And honestly, Daniel Radcliffe just seems to be too much of a nice guy, which made his character all-the-more unfitting. And on top of that, the dialogue in this film was just awful. It was so utterly stale and bland. On some terms, I found the story quite predictable.
As far as the controversial subject matter of white supremacy goes...the story didn't bring anything new to the table. Just a bunch of rehashed rhetoric that I've seen many times before in other films. Now I know this movie was supposed to have been based on a true story, so I can't really speak on the factual-basis of what happened in real life. Maybe watching a documentary about the real story would be more interesting. But the overall film didn't capture anything new or significant. Which yet again, takes me back to why this film was so predictable. With a different cast, different dialogue, different writing...maybe this film would've been better.
By the way, Toni Collette's character definitely didn't benefit this film. lol...just sayin. (super unconvincing and annoying!)