I graduated high school in 1998. I'm a metalhead, but generally prefer to dress pretty normal (black t-shirt, jeans, black boots). I did have a few piercings and long hair when I was younger, but nothing crazy. I hung out with goth kids, punk kids, skaters with giant pants sagging down, dreadlocks, big dumb chain wallets, etc. Now I blend into an office environment just fine.
Seeing kids these days and all the stuff they're into, I try to remind myself it's just a phase for 98% of them. They don't yet know who they want to be when they grow up. They try on different personalities and subcultures like you might try on clothes when shopping. It's a chance for them to spend time performing as that culture to see how well it fits for them. Most of them will spend a few months to a few years and then move on to being more "normal". I think it's important for them to have that time to figure themselves out between about 12 and 22.
For the people who are grown adults and doing this shit...free country I guess.