This is a tragedy for all sides that highlights many current issues.
1) Racial prejudices are not just black and white. Minorities are not automatically immune from prejudice. Race, religion, ethnicity, gender, sexual orientation, physical appearance and even what you say may result in unjust prejudice.
2) Guns kill. Easily. If neither George nor Trayvon had a gun, someone may have gotten bruised but likely no one would have been killed. Our current society has evolved beyond everyone needing a gun. Do we all really need guns for our own personal version of mutually assured destruction? The US Constitution needs to be updated to match current needs, not ones from 200 years ago. We are no longer the wild west. However, many are blinded by their irrational fears, leading to irrational consequences.
3) Florida has a law that allows you to commit murder legally. In Florida, get a gun, pick your target, follow them, challenge them so they "threaten" you, then stand your ground and shoot to kill so you can claim self defense. The Stand Your Ground law, while it sounds good in theory, is a pretty bad one in practice.
4) If you see a possible crime, report it to the police and follow their advice! Don't take matters into your own hands unless there is clear imminent danger to someone and there is no time to wait for professionals. It takes considerable presence of mind to do the right thing at the right time.
From what I know of this case, I think perhaps George had good intentions but his prejudices overly influenced him. Plus having a gun lead to the disastrous result of an innocent young boy losing his life. This is likely a case of a do-gooder getting carried away and doing evil instead.
It can be difficult and costly to get to the truth of a situation. Science as well as our legal system may move slowly and be expensive, but generally they result in the best truth we are capable of in their respective domains -- if not corrupted by money or power. Yes that is a big IF.
"Perhaps it is better to be un-sane and happy, than sane and un-happy. But it is the best of all to be sane and happy. Whether our descendants can achieve that goal will be the greatest challenge of the future. Indeed, it may well decide whether we have any future."
- Arthur C. Clarke