You know about the people who go around and insult artists' piercings as "ugly"?
They're the annoying vegans of the art world.
Unless the piercing considerably detracts from the art, keep your anti-piercings opinions to yourself. I don't like Christianity so much, but I'm not going to comment that opinion on a piece of art that happens to have a tiny cross somewhere in the background.
If you say the art is good and furthermore have no critique to offer, then shut up. You're done.