It's now a hate crime to attack goths or emos in parts of the U.K., equivalent to

[Elias Graves]

I think the law is going to be awfully difficult to enforce, and will probably have a hard time standing up under appeal.

I mean, what if I'm a teenage punk, but later grow out of that phase.....at what point does beating me up stop being a hate crime? Who decides who is an Emo? Can I retroactively decide to be one if I reaaallly want to sock it to the guy who beat me up? What's to stop everybody from doing that?

That's the rub. Traditionally, we labeled something a hate crime because someone was attacked for their race, religion or sexuality...things that aren't fluid. You were born a certain color, you were born gay or born a Jew. Those are things that identify you all your life and, excepting Michael Jackson and a few million Catholics who quit going to church, aren't going to change.
Being punk or emo or whatever is a lifestyle choice, and you'll likely leave behind when you realize your haircut, clothing and attitude keep you from getting a job. These are things you've actively chosen to be. I'm sorry if they get you beat up and the perps deserve jail time for doing it. But to equate that with racism or religious intolerance makes a mockery of the reasons we protect those classes of people.
Should beating up a disabled guy be a hate crime? How about a man beating on a woman? I mean, we could ascribe hate to ANY attack but there are sound and real reasons we label some things hate crimes; there's a history of societal bigotry against those things that the victim cannot control or change. Elevating to hate status crimes against societies' rebels demeans the whole logic behind codifying hate crimes.