I don't think it has much to do with the race of the person wearing a hoodie. It is more about the circumstances.
If you have your most of your head and face covered up (and hands in the hoodie pockets), then you probably look like you're up to no good. Having said that, it doesn't justify the killing of Trayvon Martin (or anyone else).
I tell young people the old saying, "Clothes Make the Man". If you dress like you're from the slum, then people will treat you like you're from the slum. If you dress in a shirt and tie, then they will treat you like a business man.
This has nothing to do with race. My black, high school teacher said it (I never saw Mr. Addison at school without his suit on). Marva Collins (famous educator) said it, others say it. I say it. CLOTHES MAKE THE MAN !
The way you dress indicates your social status and preferences. Every time I see a teenager with those pants that are hanging I say to myself, "Don't you know how you are branding yourself?"
If you still think it is about race, consider this: Three years ago (while riding Amtrak), I started the trip wearing a T-shirt. When I asked if they accepted credit cards in the dining car; they acted like I was a pariah. Before going to supper, I changed into my suit; when they asked if some people would like to sit with me (this is common on the train), they said, "Would you like to sit with this GENTLEMAN?"
Need I say more?