I think it's hard for parents to relate to that sometimes, because they grew up differently. Once upon a time, I dyed my hair a few crazy colors, like pink, blue, purple, etc. My parents wanted to kick me out of the house, and it took a while until they were willing to go out in public with me. I found it devastating and was offended that they found it embarassing to be seen with me (their words). There were a few times when they said I couldn't leave the house until I changed clothes, too. Strangely enough, now that it's normal, they said that they miss it sometimes.

To them, they might see it as weird. What they don't understand is likely your teenage desire for self-expression, which is very, very normal! It's possible that they don't understand because you don't give them a chance to understand. As you've implied, you spend a lot of time on your own at home, yes? How can they understand you better if you don't communicate with them?

My advice is that, next time this comes up, ask them what kinds of things they did/wore/etc that their parents didn't approve of. I'm sure they'll have a few stories for you, and it might bring them to a point of being more able to understand you and where you are in life right now.