I'm sorry but I don't judge films on its fictional aspects. Film writers have to make adjustments to history. Obviously, the movie makers wanted to bring in all these various characters together to make an entertaining film. What the movie captures beautifully is the fetid and frightening slums of New York at a point in history culminating in the Draft Riots. And Daniel Day Lewis gave a superb performance considering how over-the-top his character was. These kind of movies send young people running for the history books. I hope audiences don't sit there with a checklist as to what is accurate and what is not. How boring!
When I was a kid, I read Egyptian history books because I was growing up on Hollywood depictions of that era. I never believed that Victor Mature or Anne Blythe represented the royal family of Egypt! The important thing about these movies is to encourage interest.
I hope audiences don't sit there with a checklist as to what is accurate and what is not. And yet we have people here holding up scenes from the movie as accurate depictions of events. You liked the movie? Fine. I didn't think it was great Scorsese, but then I think Scorsese hasn't made a great movie since about Casino.