Why do people automatically suggest.....?

why do most people automatically suggest that if someone wants/has a lower back tattoo...other wise known as a tramp stamp...with being slutty. Heck my best friend has a simple, cute tattoo on her lower back and she isn't even close to being a slut...for God's sake she wear a purity ring! I don't see why most people automatically have to ume a person has/wants one to show off promiscuity