A few other points:

Paulie Vario was himself a cocaine dealer according to Al D'Arco's book. Paulie offered to cut him in on a coke deal. So as we all know, the ban on drugs was a farce. Vario and Burke would have hit Hill just to avoid getting caught.

Henry Hill was snorting heroin for 7 or 8 months around the time of his drug arrest according to his book Gangsters and Goodfellas. So whoever said above that Henry was a junkie was correct.

While Goodfellas is one of the greatest movies ever, it fictionalizes a lot of the mafia elements and leaves out a lot of important facts in the books.