This one of the areas where David Chase took some "artistic liberties". In real life,one of the protocols is that you don't lay hands on a made guy. Now granted,a lot of so-called rules are overlooked depending on who breaks them,but the "hands off" rule,from what I've read and heard,is pretty much non-negotiable.

(And yes,I know that Anastasia once slapped Carlo Gambino,but it was Carlo who chose not to pursue it). My point is that Tony did it at least four times. Phil,Ralph Ciffaretto(after he killed the stripper),Paulie,(after he came from the steambath w/ Pussy,and Coco(after he insulted Meadow).

Paulie even told Tony "now get your fuckin hands off me",and Ralph screamed at Tony "I'm a made guy". Even Sil told Tony that going after Ralph was wrong.
The more practical question is that,in the Leotardo incident what could New York do about it? A sitdown is out of the question because Tony is a Boss,so who would have the authority to conduct it,and furthermore to assess a punishment if deemed necessary?