Tattoos and piercings in the workplace should go in the same category as apparel. Different occupations require different styles and levels of professional dress.
Some people have to wear suits, others have to wear uniforms. Does it cramp your individual style? Sure it does. But you follow company policy and wear what you’re required to wear if you want to work at that place… even if the color of the uniform drains your face of all its color.

In the same way, some businesses require tats and piercings to be covered. Does it cramp your individual style? Sure it does. But you follow company policy and do what you’re required to do if you want to keep working at that place.
It’s not always discrimination; sometimes it’s just company policy.