How did I get my tattoo (legal question)?

I was just over at “Do you regret your tattoo” in IMHO and it got me thinking. When I got it (not the case any longer, but then) tattoos were illegal in NYC. To the best of my knowledge. Yet my friend sent me around to his friend, to a place on St. Marks (not exactly out of the way) with a big neon sign that said TATTOOS.

Now I knew a lot of inked folks, and a lot of inkers, but somehow I never wrapped my mind around the concept that it was illegal but there were god knows how many neon signs for TATTOOS all over town. I can think of a lot of illegal things freely available in NY but DRUGS AND SEX don’t usually have neon signs.

How did this work, legally?