conformism in the workplace

I recently have had my ears peirced -- they are now peirced 3 times on each ear. I really like them-but i didnt realize until after i got them that they really don't like them at the place where I work. they technically can't fire me for them or anything, but it still really upsets most of my supervisors and managers.. I can't understand this at all ! I don't see why having peircings should in any way effect my job performance. I only work at a fast food place, but we are still not allowed to have more than one peircing per ear, no visbable tatoos, and no "crazy" hair colours. I really think that they should lower these standards, especially since many teenagers experiment with peircings and hair colours, and teenagers are the main people who would want to work at a fast food place anyways.
It bugs me that they insist on conformism in these workplaces, by basically asking all workers to look the same as each other. we all must wear the standard uniform at all times, (we can't go out front even if we're just missing our hat,) no jewlery of any kind, no nail polish, and of course no peircings, crazy hair colours, or visible tatoos. When we have had inspections in our work there has actually been points taken of examination of our store based on my two too many peircings per ear. I think this is so discriminatory-- I dont know why they care so much that we all look the same. Do you think that it really gives the image of professionalism by having all the workers seem like the same person ? I think that it makes us seem like we're not real people, and we don't have lives outside of work.