The movie would have been 5 hrs long if they put everything in. So they had to pick and choose. And since pistone knew by following mirra he would have never infiltrated the way he did because mirra was a mean homicidal maniac who was loathed by his fellow gangsters so is tone developed lefty didn't hurt that mirra got thrown back in the can during pistones early years
I get your point, but they could've thrown in a scene about Mirra. Even if it were just a few minutes long. They could have written in a part about him fleeing NY, then getting caught by the FBI soon after, and going to prison in 1977. Then maybe had Lefty, Black, and the others talk about how horrible of a person he was. Meh, I dont know, I guess they know what they're doing, but I really think they should have at least mentioned him in the film.
