I disagree. I don't see it as fashion because you don't put it on daily or change it with the season, it may have cultural or religious significance, and often the most significant ones (or portions) are hidden from view.
It is, however, a part of the body, and I wouldn't come here and tell someone their nose was too big.
It is also a work of art, and I wouldn't come here to debate the artistic merit of Duchamp's readymades.
It may have religious or spiritual significance, and I wouldn't tell a priest his clerical collar makes him look "holier than though."
I love to critique tattoos and am a bit of an enthusiast, but I save my opinions for the tattoo forums where they belong.