Most Helpful Guy
They want to display a conservative business look. Most people, myself included, can't take someone seriously with certain kinds of tattoos and piercings. The person I would prefer to do business with wouldn't have a tattoo of snake wrapped around his neck, tear drops on his face, or "f*** off" on his knuckles.
Businesses are allowed to have a dress code and it isn't discriminatory. If they tell you to cover them up, it's their right. The bosses run things, not the employees or potential employees. When you get tattoos and piercings, you should know that most workplaces will not accept it, but people still do it.