"Julie Roberts, Jessica Alba, David Beckham and Blake Shelton all have tattoos so how come it's accepted for them and not Trayvon? I'm going to assume that age isn't the issue."
The people you listed do not have a long history of holding complete distain for their communities, the rule of law, women (i.e. rapping about ho's, b!tches, shooting cops), having to hold their pants up with one hand, etc. etc. etc. the list goes on. So, in short, it is not an age issue.