As far as I can tell from some Googling, this is what happened:
-Some crazy sent videos of a "documentary" denying the Holocaust out to all sorts of politicians.
-Kaptur received one, and her office sent back a generic form letter with some personalization about it listed here:
So clearly what occurred was the letter was some sort of generic mad libs thing that some staffer filled in with references to the video. It's almost certain Kaptur never either saw the film or wrote the letter, and that any of her staffers even saw the film either. Considering the generic and harmless sounding title, it's not too much of a stretch to see that they simply assumed it was some amateur WWII documentary and thus sent out the fill in the blanks form letter with some notes about the video copy and pasted. Seriously read that thing and then replace the name of the creator and film with any creator and documentary.
Basically evidence of nothing aside from that Kaptur has some lazy staffers.