Al Norris, I'll accept the separation of powers, but only partially.
The prosecutor had to sign off on the plea deal. That's part of charging.
The judge could have refused to accept it; or, the judge could have thrown out the charge.
But the charging part of enforcement is not being uniformly applied. When the defendant has a legal and PR machine available, NYC is quietly burying the problem.
I'm not naive enough to think this doesn't happen in many places. However, I do suspect that part of the DA's motivation to deal in this particular case is that Meckler could have really thrown up some interesting challenges to NY state's effective ban on on-resident carry, and NYC's track record with regard to FOPA.
(Not that I think Meckler really would have fallen under FOPA, but discovery of other NYC cases could have been interesting.)